Unit 2 Amazing numbers单元知识总结及重点易错专项训练2026-2027学年沪教版八年级英语上册

**基本信息** 聚焦数量表达核心考点，以“规则总结+分层训练+易错突破”构建系统性方法体系，知识逻辑从词汇到语法再到句型应用，层层递进，助力语言能力与思维品质提升。 **专项设计** |模块|题量/典例|方法提炼|知识逻辑| |----|-----------|----------|----------| |10大考点|90题（每考点基础/提升/拓展各3题）|基数词单复数规则、序数词拼写口诀、分数表达规则、percent主谓一致、increase/reduce与by/to辨析|从核心词汇（hundred/thousand等）到语法规则（基数词/序数词/分数/百分数），再到句型应用（询问人口/表达数量比较），形成“概念-规则-应用”递进链条|

沪教版八年级上册 Unit 2 Amazing numbers 单元知识总结及重点易错专项训练 ■ ■ ■ ■ ■ ■ ■ 说明：本练习紧扣最新教材精选 10 个重点易错考点，每个考点含基础题×3、提升题×3、拓展题×3，共 90 题。 第一部分　单元重点梳理 一、重点单词（Section A & B 核心词汇） 单词 词性 释义 amazing adj. 惊人的；了不起的 number n. 数字；数量 digit n. 数字（0–9 中的单个数字） hundred n. 百 thousand n. 千 million n. 百万 billion n. 十亿 percent n. 百分之…… population n. 人口 flight n. 航程；航班 schedule n. 日程安排；时刻表 challenge v./n. 向……挑战；挑战 prize n. 奖赏；奖励 promise v./n. 承诺；保证 chessboard n. 国际象棋棋盘 hesitation n. 犹豫 wonder v. 想知道；琢磨 exactly adv. 准确地；确切地 currently adv. 目前；当前 sharply adv. 急剧地；突然大幅度地 increase v. 增加；增长 reduce v. 减少；降低 calculate v. 计算 represent v. 代表；表示 二、重点短语（高频短语） 短语 释义 flight schedule 航班时刻表 role in daily life 在日常生活中的作用 amazing numbers 惊人的数字 types of numbers 数字的种类 challenge sb. to a game 向某人挑战一场比赛 one grain of rice 一粒米 double the amount 加倍数量 gold or silver 金银 without hesitation 毫不犹豫 figure out 算出；弄清楚 work out 计算出；解决 add up to 总计；加起来等于 on average 平均 in total 总共；总计 as many as 多达；和……一样多 at least 至少 at most 至多；最多 twice as much 两倍多 take...for example 以……为例 round up/down 向上 / 向下取整 三、重点句型（常考交际与功能句型） 1. 询问人口：What's the population of Qingdao?（青岛的人口是多少？） 2. 表达数量：The population of this city is over 10 million.（这座城市的人口超过一千万。） 3. 表达百分比：About 30 percent of the students prefer math.（大约 30% 的学生更喜欢数学。） 4. 比较数量：This number is twice as large as that one.（这个数字是对方的两倍大。） 5. 比较数量：There are fewer boys than girls in our class.（我们班男生比女生少。） 6. 询问数量：How many people are there in your family?（你家有几口人？） 7. 询问百分比：What percentage of the earth is covered by water?（地球百分之多少被水覆盖？） 8. 描述计算过程：First, add these numbers together.（首先，把这些数字相加。） 9. 表达增加：The population increased by 2 million last year.（去年人口增加了两百万。） 10. 表达约数：There are about two thousand students in our school.（我们学校大约有 2000 名学生。） 四、重点语法（单元核心语法） 1. 基数词（Cardinal numbers）：hundred / thousand / million / billion 等，前面有具体数字时一律用单数（two thousand）；表示模糊数量时用复数加 of（thousands of）。 2. 序数词（Ordinal numbers）：first, second, third, fifth, eighth, ninth, twelfth, twentieth 等；口诀“基变序，有规律；一二三特殊记；八去 t，九去 e；f 把 ve 替；ty 变成 tie”。 3. 分数表达：分子用基数词，分母用序数词；分子大于 1 时，分母加 s（two thirds, three fourths）。 4. 百分数：percent 单复数同形，永远不加 s；百分数 + of + 名词，谓语动词与 of 后面的名词保持一致。 5. population 用法：问人口用 What's the population of...? 不用 How many；population 作主语时谓语动词用单数。 6. 倍数比较：twice / three times as + 形容词原级 + as（A is twice as large as B）。数量多少用 larger / smaller，不用 more。 7. 运算动词：add（加）、subtract（减）、multiply（乘）、divide（除）、calculate（计算）、work out / figure out（算出）、add up to（总计）。 8. 增减表达：increase / reduce by 表示“净增减的量”；increase / reduce to 表示“增减到的结果”。 第二部分　常考易错专项训练（10 大考点） 说明：每题均为选择题，选项 A（红）/ B（蓝）/ C（绿）/ D（橙）四色区分。基础题◇ / 提升题▷ / 拓展题★，层次递进。 考点一：考点一：基数词大数表达（hundred / thousand / million / billion 的具体数字用法与模糊数量 thousands of 的区别） 基础题：（选择题） ◇（ ）1. There are about two _______ students in our school. A. thousand B. thousands C. thousand of D. thousands of ◇（ ）2. _______ people visit the museum in Wuhan every year. A. Two thousand of B. Thousands of C. Two thousands D. Thousand of ◇（ ）3. My cousin saved five _______ yuan to buy a new bike. A. hundreds B. hundred of C. hundred D. hundreds of 提升题：（选择题） ▷（ ）1. The small town has a population of about three _______. A. thousands B. thousand of C. thousands of D. thousand ▷（ ）2. _______ birds fly to the south in winter. A. Thousands of B. Thousand of C. Two thousand of D. Two thousands ▷（ ）3. We need two _______ rice for the chess game on the chessboard. A. hundreds B. hundred C. hundred of D. hundreds of 拓展题：（选择题） ★（ ）1. About four _______ workers built the new bridge in Xiamen. A. thousands B. thousands of C. thousand D. thousand of ★（ ）2. _______ of the students in our school like math. A. Thousand B. Two thousand C. Two thousands D. Thousands ★（ ）3. Lily counted _______ books in the library in Jinan. A. thousand B. thousands C. thousand of D. thousands of 考点二：考点二：序数词构成与特殊拼写（first, second, third, fifth, eighth, ninth, twelfth, twentieth 等） 基础题：（选择题） ◇（ ）1. Today is my sister's _______ birthday. A. twelve B. twelfth C. twelveth D. twelves ◇（ ）2. He lives on the _______ floor of the building. A. nineth B. nine C. ninth D. nineths ◇（ ）3. This is the _______ time for Chen Wei to win the prize. A. eight B. eigh C. eightth D. eighth 提升题：（选择题） ▷（ ）1. January is the _______ month of a year. A. first B. one C. oneth D. frist ▷（ ）2. Her birthday is on the _______ of May. A. twenty B. twentieth C. twentith D. twentieth ▷（ ）3. The _______ boy in the line is my brother Zhou Kai. A. five B. fiveth C. fifth D. fivst 拓展题：（选择题） ★（ ）1. Olivia came _______ in the running race. A. two B. twoth C. secend D. second ★（ ）2. This is my _______ day to learn about amazing numbers. A. third B. three C. threeth D. thirth ★（ ）3. The _______ month of the year is December. A. twelveth B. twelfth C. twelve D. twelf 考点三：考点三：分数表达（分子用基数词，分母用序数词；分子大于 1 时分母加 s） 基础题：（选择题） ◇（ ）1. _______ of the students in our class are from Kunming. A. One thirds B. One three C. One third D. First third ◇（ ）2. About _______ of the earth is covered by water. A. three fourth B. third fourth C. three four D. three fourths ◇（ ）3. _______ of the books in the library are new. A. Two thirds B. Two third C. Second thirds D. Two threes 提升题：（选择题） ▷（ ）1. _______ of the cake is for Bella. A. One halves B. One half C. First half D. One halves ▷（ ）2. _______ of the students passed the math test. A. Three fifth B. Third fifths C. Three fifths D. Three five ▷（ ）3. Only _______ of the work is finished. A. one four B. first fourth C. one fourths D. one fourth 拓展题：（选择题） ★（ ）1. _______ of the people in the city use the new system. A. Two fifths B. Two fifth C. Second fifths D. Two fives ★（ ）2. _______ of the money belongs to the school. A. Three quarter B. Three quarters C. Third quarters D. Three four ★（ ）3. _______ of the class went to the science museum in Jinan. A. One fives B. First fifth C. One fifth D. One five 考点四：考点四：百分数 percent 及主谓一致（percent 单复数同形；谓语与 of 后名词一致） 基础题：（选择题） ◇（ ）1. About 30 _______ of the students in our school like reading. A. percents B. percentage C. percents D. percent ◇（ ）2. _______ of the water is clean. A. Ninety percent B. Ninety percents C. Ninety percentage D. Ninety percents ◇（ ）3. Two _______ of the apples are red. A. percents B. percent C. percentage D. percents 提升题：（选择题） ▷（ ）1. About 70 _______ of the earth is covered by water. A. percents B. percentage C. percent D. percents ▷（ ）2. _______ of the boys in our class play basketball. A. Fifty percents B. Fifty percentage C. Fiftieth percent D. Fifty percent ▷（ ）3. Only 10 _______ of the food is left. A. percent B. percents C. percentage D. percents 拓展题：（选择题） ★（ ）1. _______ of the people in Xiamen use digital payments. A. Eighty percents B. Eighty percent C. Eighty percentage D. Eightieth percent ★（ ）2. About 25 _______ of the students walk to school. A. percents B. percentage C. percent D. percents ★（ ）3. Ninety _______ of the work is done by Lily. A. percents B. percentage C. percents D. percent 考点五：考点五：population 的用法（问人口用 What's the population of...? 谓语用单数） 基础题：（选择题） ◇（ ）1. — _______ the population of Qingdao? — About 10 million. A. What's B. How many is C. How much is D. What are ◇（ ）2. The population of the city _______ over 5 million. A. are B. is C. were D. be ◇（ ）3. — _______ the population of your hometown? — About 2 million. A. How many is B. How much are C. What is D. What are 提升题：（选择题） ▷（ ）1. The population of Wuhan _______ larger than that of Xiamen. A. are B. were C. be D. is ▷（ ）2. — _______ the population of Kunming? — It's about 8 million. A. What's B. How many C. How much D. Which is ▷（ ）3. The population of our town _______ about 30,000. A. are B. is C. have D. were 拓展题：（选择题） ★（ ）1. — What's the population of Jinan? — _______ about 9 million. A. They are B. There is C. It's D. Are ★（ ）2. The population of the village _______ very small. A. are B. were C. be D. is ★（ ）3. — _______ the population of the island? — Only 1,000. A. What is B. How many C. How much D. Where is 考点六：考点六：倍数与数量比较（twice / three times as + 原级 + as；数量多少用 larger / smaller） 基础题：（选择题） ◇（ ）1. This box is _______ as that one. A. twice heavy B. twice as heavy C. two as heavy D. twice as heavier ◇（ ）2. There is _______ water in this bottle than in that one. A. fewer B. many C. less D. few ◇（ ）3. The number of boys is _______ than that of girls. A. more B. many C. much D. larger 提升题：（选择题） ▷（ ）1. The blue bag is _______ as the red one. A. three times as big B. three time as big C. three times big D. three as big ▷（ ）2. There are _______ students in Class 1 than in Class 2. A. many B. more C. much D. less ▷（ ）3. Lily's book is _______ as Chen Wei's. A. twice thick B. two as thick C. twice as thick D. twice as thicker 拓展题：（选择题） ★（ ）1. This building is _______ as that old one. A. four time as tall B. four times tall C. four as tall D. four times as tall ★（ ）2. The population of Qingdao is _______ as that of the small town. A. ten times as large B. ten time as large C. ten times large D. ten as large ★（ ）3. There is _______ milk in the glass than in the cup. A. fewer B. less C. few D. many 考点七：考点七：数学运算动词辨析（add / subtract / multiply / divide / calculate / work out / figure out） 基础题：（选择题） ◇（ ）1. Please _______ 3 and 5, and you get 8. A. subtract B. divide C. add D. multiply ◇（ ）2. Can you _______ this math problem? It's difficult. A. add up B. subtract C. multiply D. work out ◇（ ）3. We use a computer to _______ the numbers. A. calculate B. count C. figure D. add up 提升题：（选择题） ▷（ ）1. If you _______ 10 by 2, you get 5. A. multiply B. divide C. add D. subtract ▷（ ）2. Let's _______ 6 from 9. The answer is 3. A. add B. multiply C. subtract D. divide ▷（ ）3. They _______ 4 by 3 and got 12. A. added B. divided C. subtracted D. multiplied 拓展题：（选择题） ★（ ）1. The numbers _______ to 100 in total. A. add up B. work out C. subtract D. divide ★（ ）2. Olivia tried to _______ how many grains of rice there were. A. add up B. figure out C. divide D. subtract ★（ ）3. The teacher asked us to _______ the total of the numbers. A. subtract B. multiply C. calculate D. divide 考点八：考点八：increase / reduce 与 by / to 辨析（by 表净增减量；to 表变化结果） 基础题：（选择题） ◇（ ）1. The population of the city increased _______ 2 million last year. A. to B. for C. with D. by ◇（ ）2. The price _______ from 10 yuan to 8 yuan. A. reduced B. increased C. added D. doubled ◇（ ）3. The number of students _______ to 500 this year. A. reduced B. increased C. subtracted D. divided 提升题：（选择题） ▷（ ）1. The temperature rose _______ 5 degrees. A. to B. for C. by D. with ▷（ ）2. The price dropped _______ 20 yuan after the sale. A. to B. for C. with D. by ▷（ ）3. The population _______ to 3 million in 2020. A. increased B. reduced C. subtracted D. divided 拓展题：（选择题） ★（ ）1. The cost _______ by 10% this month. A. reduced B. increased C. subtracted D. divided ★（ ）2. The number of birds _______ from 100 to 80. A. increased B. added C. reduced D. doubled ★（ ）3. The temperature fell _______ 3 degrees at night. A. to B. for C. with D. by 考点九：考点九：challenge / promise / wonder / without hesitation 等动词与短语搭配 基础题：（选择题） ◇（ ）1. The king _______ the old man to a chess game. A. challenged B. promised C. wondered D. replied ◇（ ）2. Bella _______ to help her friend with the math homework. A. challenged B. promised C. wondered D. replied ◇（ ）3. Zhang Hao agreed to go with us _______. A. with hesitation B. in hesitation C. without hesitation D. no hesitation 提升题：（选择题） ▷（ ）1. I _______ how many people live in this city. A. challenge B. promise C. reply D. wonder ▷（ ）2. The young man won a _______ in the running race. A. prize B. challenge C. hesitation D. schedule ▷（ ）3. Lily _______ to her friend's email yesterday. A. challenged B. replied C. promised D. wondered 拓展题：（选择题） ★（ ）1. Zhou Kai _______ the boy to a table tennis game. A. promised B. replied C. challenged D. wondered ★（ ）2. Olivia _______ the old man any prize if he won the game. A. challenged B. replied C. wondered D. promised ★（ ）3. Chen Wei said yes _______ when we asked him to join us. A. without hesitation B. with hesitation C. in hesitation D. no hesitation 考点十：考点十：数量短语辨析（at least / at most / as many as / on average / in total） 基础题：（选择题） ◇（ ）1. There are _______ 30 students in our class. A. at most B. at least C. as many as D. on average ◇（ ）2. You should eat _______ two apples a day. A. at least B. as many as C. at most D. on average ◇（ ）3. _______ , each student has 3 classes a day. A. At least B. At most C. As many as D. On average 提升题：（选择题） ▷（ ）1. There are _______ 1,000 books in the library. A. as many as B. at most C. on average D. at least ▷（ ）2. _______ , we spend two hours on homework. A. At most B. On average C. As many as D. At least ▷（ ）3. The trip takes _______ three days. A. at most B. on average C. at least D. as many as 拓展题：（选择题） ★（ ）1. In _______ , there are 50 students in the grade. A. average B. least C. most D. total ★（ ）2. The small village has _______ 200 people. A. at most B. at least C. on average D. as many as ★（ ）3. We need _______ five volunteers for the activity. A. at most B. at least C. on average D. in total 第三部分　详细参考解析 以下解析按考点与题型排列，序号各自独立。 考点一：考点一：基数词大数表达（hundred / thousand / million / billion 的具体数字用法与模糊数量 thousands of 的区别） 基础题： 1. 【答案】A 【解析】具体数字 two 后面接 hundred / thousand 等不加 s，也不接 of，故选 thousand。 2. 【答案】B 【解析】表示模糊的“成千上万”用 thousands of，前面不能再加具体数字，故选 Thousands of。 3. 【答案】C 【解析】具体数字 five 后 hundred 用单数，不加 of，故选 hundred。 提升题： 1. 【答案】D 【解析】具体数字 three 后 thousand 用单数，不加 of，故选 thousand。 2. 【答案】A 【解析】泛指“成千上万的鸟”用 Thousands of，其余形式均错误。 3. 【答案】B 【解析】具体数字 two 后 hundred 用单数，故选 hundred。 拓展题： 1. 【答案】C 【解析】具体数字 four 后 thousand 用单数，不加 of，故选 thousand。 2. 【答案】D 【解析】“成千上万的学生”用 Thousands of，此处 of 已出现在题干，故选 Thousands。 3. 【答案】A 【解析】具体数字 one（隐含）后 thousand 用单数，故选 thousand。 考点二：考点二：序数词构成与特殊拼写（first, second, third, fifth, eighth, ninth, twelfth, twentieth 等） 基础题： 1. 【答案】B 【解析】第十二用 twelfth，ve 变 f 再加 th，故选 twelfth。 2. 【答案】C 【解析】第九为 ninth，九去 e 加 th，故选 ninth。 3. 【答案】D 【解析】第八为 eighth，八去 t 加 th，故选 eighth。 提升题： 1. 【答案】A 【解析】第一为 first，属于特殊变化，故选 first。 2. 【答案】B 【解析】第二十为 twentieth，ty 变 tie 再加 th，故选 twentieth。 3. 【答案】C 【解析】第五为 fifth，ve 变 f 加 th，故选 fifth。 拓展题： 1. 【答案】D 【解析】第二为 second，属于特殊变化，故选 second。 2. 【答案】A 【解析】第三为 third，属于特殊变化，故选 third。 3. 【答案】B 【解析】第十二为 twelfth，故选 twelfth。 考点三：考点三：分数表达（分子用基数词，分母用序数词；分子大于 1 时分母加 s） 基础题： 1. 【答案】C 【解析】三分之一为 one third，分子为 1 时分母不加 s，故选 One third。 2. 【答案】D 【解析】四分之三为 three fourths，分子大于 1 分母加 s，故选 three fourths。 3. 【答案】A 【解析】三分之二为 two thirds，分子大于 1 分母加 s，故选 Two thirds。 提升题： 1. 【答案】B 【解析】二分之一为 one half（也可用 a half），half 不变复数，故选 One half。 2. 【答案】C 【解析】五分之三为 three fifths，分子大于 1 分母加 s，故选 Three fifths。 3. 【答案】D 【解析】四分之一为 one fourth（或 a quarter），分子为 1 分母不加 s，故选 one fourth。 拓展题： 1. 【答案】A 【解析】五分之二为 two fifths，分子大于 1 分母加 s，故选 Two fifths。 2. 【答案】B 【解析】四分之三也可用 three quarters，quarter 变复数，故选 Three quarters。 3. 【答案】C 【解析】五分之一为 one fifth，分子为 1 分母不加 s，故选 One fifth。 考点四：考点四：百分数 percent 及主谓一致（percent 单复数同形；谓语与 of 后名词一致） 基础题： 1. 【答案】D 【解析】percent 单复数同形，永远不加 s，故选 percent。 2. 【答案】A 【解析】百分之九十为 ninety percent，不加 s，故选 Ninety percent。 3. 【答案】B 【解析】percent 不加 s，故选 percent。 提升题： 1. 【答案】C 【解析】百分之七十为 seventy percent，percent 不加 s，故选 percent。 2. 【答案】D 【解析】百分之五十为 fifty percent，不加 s，故选 Fifty percent。 3. 【答案】A 【解析】percent 单复数同形，不加 s，故选 percent。 拓展题： 1. 【答案】B 【解析】百分之八十为 eighty percent，不加 s，故选 Eighty percent。 2. 【答案】C 【解析】percent 不加 s，故选 percent。 3. 【答案】D 【解析】percent 单复数同形，不加 s，故选 percent。 考点五：考点五：population 的用法（问人口用 What's the population of...? 谓语用单数） 基础题： 1. 【答案】A 【解析】问人口用 What's the population of...? 固定句型，故选 What's。 2. 【答案】B 【解析】population 作主语时谓语用单数，故选 is。 3. 【答案】C 【解析】问人口用 What is the population of...? 谓语用单数，故选 What is。 提升题： 1. 【答案】D 【解析】population 作主语谓语用单数，故选 is。 2. 【答案】A 【解析】问人口用 What's the population of...? 故选 What's。 3. 【答案】B 【解析】population 作主语谓语用单数，故选 is。 拓展题： 1. 【答案】C 【解析】population 视为单数，回答用 It's，故选 It's。 2. 【答案】D 【解析】population 作主语谓语用单数，故选 is。 3. 【答案】A 【解析】问人口用 What is the population of...? 故选 What is。 考点六：考点六：倍数与数量比较（twice / three times as + 原级 + as；数量多少用 larger / smaller） 基础题： 1. 【答案】B 【解析】倍数比较用“倍数 + as + 原级 + as”，故选 twice as heavy。 2. 【答案】C 【解析】water 不可数，用 less 表示“更少”，故选 less。 3. 【答案】D 【解析】表示数量“更大”用 larger，不用 more，故选 larger。 提升题： 1. 【答案】A 【解析】三倍用 three times as + 原级 + as，故选 three times as big。 2. 【答案】B 【解析】students 可数，比较“更多”用 more，故选 more。 3. 【答案】C 【解析】倍数比较用 twice as + 原级 + as，故选 twice as thick。 拓展题： 1. 【答案】D 【解析】四倍用 four times as + 原级 + as，故选 four times as tall。 2. 【答案】A 【解析】表示数量大用 large，倍数比较用 ten times as large as，故选 ten times as large。 3. 【答案】B 【解析】milk 不可数，比较“更少”用 less，故选 less。 考点七：考点七：数学运算动词辨析（add / subtract / multiply / divide / calculate / work out / figure out） 基础题： 1. 【答案】C 【解析】3 加 5 等于 8，用 add，故选 add。 2. 【答案】D 【解析】“解出、算出”数学题用 work out，故选 work out。 3. 【答案】A 【解析】“计算”数字用 calculate，故选 calculate。 提升题： 1. 【答案】B 【解析】10 除以 2 得 5，用 divide，故选 divide。 2. 【答案】C 【解析】从 9 减 6 得 3，用 subtract，故选 subtract。 3. 【答案】D 【解析】4 乘 3 得 12，用 multiply 的过去式 multiplied，故选 multiplied。 拓展题： 1. 【答案】A 【解析】“总计达”用 add up to，此处为 add up，故选 add up。 2. 【答案】B 【解析】“弄清楚、算出”用 figure out，故选 figure out。 3. 【答案】C 【解析】“计算”总数用 calculate，故选 calculate。 考点八：考点八：increase / reduce 与 by / to 辨析（by 表净增减量；to 表变化结果） 基础题： 1. 【答案】D 【解析】increase by 表示“净增加了”，后接增加量，故选 by。 2. 【答案】A 【解析】从 10 元降到 8 元是“减少”，用 reduced，故选 reduced。 3. 【答案】B 【解析】人数“增加到”500 用 increased to，故选 increased。 提升题： 1. 【答案】C 【解析】rose by 表示“上升了（净增量）”，故选 by。 2. 【答案】D 【解析】dropped by 表示“下降了（净减量）”，故选 by。 3. 【答案】A 【解析】“增加到”3 百万用 increased to，故选 increased。 拓展题： 1. 【答案】B 【解析】成本“增加了”10% 用 increased by，故选 increased。 2. 【答案】C 【解析】从 100 减到 80 是“减少”，用 reduced，故选 reduced。 3. 【答案】D 【解析】fell by 表示“下降了（净减量）”，故选 by。 考点九：考点九：challenge / promise / wonder / without hesitation 等动词与短语搭配 基础题： 1. 【答案】A 【解析】“向某人挑战”用 challenge sb. to，过去式 challenged，故选 challenged。 2. 【答案】B 【解析】“承诺做某事”用 promise to do，故选 promised。 3. 【答案】C 【解析】“毫不犹豫”固定用 without hesitation，故选 without hesitation。 提升题： 1. 【答案】D 【解析】“想知道”用 wonder，故选 wonder。 2. 【答案】A 【解析】“获奖”用 win a prize，故选 prize。 3. 【答案】B 【解析】“回复邮件”用 reply to，过去式 replied，故选 replied。 拓展题： 1. 【答案】C 【解析】“向某人挑战”用 challenge，故选 challenged。 2. 【答案】D 【解析】“承诺给奖赏”用 promise sb. sth.，故选 promised。 3. 【答案】A 【解析】“毫不犹豫”用 without hesitation，故选 without hesitation。 考点十：考点十：数量短语辨析（at least / at most / as many as / on average / in total） 基础题： 1. 【答案】B 【解析】“至少 30 人”用 at least，故选 at least。 2. 【答案】C 【解析】“最多两个苹果”用 at most，故选 at most。 3. 【答案】D 【解析】“平均”用 on average，故选 On average。 提升题： 1. 【答案】A 【解析】“多达 1000 本”用 as many as，故选 as many as。 2. 【答案】B 【解析】“平均”花两小时用 on average，故选 On average。 3. 【答案】C 【解析】“至少三天”用 at least，故选 at least。 拓展题： 1. 【答案】D 【解析】“总共”用 in total，故选 total。 2. 【答案】A 【解析】“至多 200 人”用 at most，故选 at most。 3. 【答案】B 【解析】“至少五名志愿者”用 at least，故选 at least。 Unit 2 Amazing numbers 专项训练　第 页 学科网（北京）股份有限公司 $