Unit 5 Saving animals in danger 单元语法（It作形式主语和adj+enough+to+v）-2025-2026学年八年级英语下册单元重难点易错题精练（沪教版）

**基本信息** 初中英语Unit 5单元卷，聚焦It作形式主语和adj+enough+to+v核心语法，结合动物保护主题，通过多样题型实现基础巩固与能力提升，适配单元复习需求。 **题型特征** |题型|题量/分值|知识覆盖|命题特色| |----|-----------|----------|----------| |单项选择|20/20|It作形式主语（of/for辨析）、adj+enough+to结构|梯度设计，从基础语法辨析（如第2题of/for选择）到语境应用（如第19题描述偷猎者行为）| |完成句子|10/20|句型转换、汉译英（如It is+adj+for/of sb to do）|语法与意义结合，如第28题合并句子巩固It is careless of sb结构| |短文填空|10/20|名词复数、比较级等语法，动物知识|融入动物王国世界纪录素材，体现文化意识与思维品质，如第33题考查物主代词its|

Unit 5 Saving animals in danger It作形式主语和adj+enough+to+v （时间：40分钟，满分：60分） 一、单项选择(本大题共20小题，每小题1分，共20分) 1．It is ________ of Tom to be late for school again. A．careless B．important C．difficult D．necessary 2．It is clever ________ the girl ________ find the way home by herself. A．for; to B．of; to C．for; for D．of; of 3．It is necessary ________ students ________ get up early every day. A．of; to B．for; to C．of; for D．for; for 4．It is wrong ________ you ________ laugh at others. A．for; to B．of; to C．for; for D．of; of 5．The box is ________ heavy ________ the little girl to carry. A．too; to B．enough; to C．too; for D．enough; for 6．It is meaningful ________ us ________ take part in the volunteer activities. A．for; to B．of; to C．for; for D．of; of 7．The boy is ________ to reach the apple on the tree. A．enough tall B．tall enough C．too tall D．tall too 8．It’s patient ________ you ________ wait for me for so long. A．for; to B．of; to C．for; wait D．of; wait 9．—It’s generous _________ you to offer free meals to the homeless.   —I think it’s meaningful _________ us to do something for others. A．of; for B．for; of C．of; to D．to; for 10．It’s necessary _________ a second language well if you want to work abroad. A．learn B．learning C．to learn D．learned 11．_________ is important for everyone to protect the environment. A．This B．That C．It D．There 12．The girl is ________ to go to school. A．enough old B．old enough C．too old D．so old 13．It is very kind ________ you to volunteer at the wildlife rescue center every weekend. A．of B．for C．to D．with 14．The rescue team worked day and night, and finally the injured crane was ________ to fly back to the wild. A．enough strong B．strongly enough C．strong enough D．enough strongly 15．—Why didn’t you stop the boy from throwing rocks at the duck? —Because I was not ________ to argue with him at that time. A．enough brave B．brave enough C．enough bravely D．bravely enough 16．The box is ________ heavy for the little boy ________ carry. A．too; to B．enough; to C．so; that D．such; that 17．The boy was ________ brave enough to stop the hunter from killing the bird. A．not B．no C．never D．don't 18．It is wrong ________ people to buy fur coats made from endangered wild animals. A．of B．for C．to D．with 19．It was extremely cruel ________ the poachers to kill the mother elephant for its tusks. A．of B．for C．to D．with 20．It is not easy ________ many animal species to survive in the wild. A．of B．for C．to D．with 二、完成句子(本大题共10小题，每小题2分，共20分) 21．给老人让座是正确的。 It is right ________ ________ ________ seats to the elderly. 22．你犯这样的错误真是太粗心了。 It is really careless ________ you ________ ________ such a mistake. 23．对孩子们来说在河里游泳是危险的。 It is dangerous ________ children ________ ________ in the river. 24．你能帮我拎这个重箱子，真是太善良了。 It is very kind ________ you ________ ________ me carry the heavy box. 25．对我们来说每天锻炼很重要。 It is important ________ us ________ ________ exercise every day. 26．He is generous to share his food with us.   It’s ________ ________ ________ to share his food with us. 27．在生活中他足够勇敢去面对各种困难。 In life, he ________ to face all kinds of difficulties. 28．Liu Ming left his homework at home again. He was careless. (合并为一句)   It ________ ________ ________ Liu Ming to leave his homework at home again. 29．每天练习说英语对我们来说很有必要。 →________ ________ for us to practice speaking English every day. 30．这个医生足够耐心，解答了所有问题。(完成译句) The doctor is ________ ________ to answer all the questions. 三、短文填空(本大题共10小题，每小题2分，共20分) 阅读下面短文，在空白处填入一个适当的单词或括号内单词的正确形式。 There are world records at the Olympic Games. But what are the world 31 (record) in the animal kingdom (王国)? The 32 (large) and heaviest animal on the earth is the blue whale. It weighs (重) between 110 and 120 tons. 33 (it) heart is the size of a small car. It has the biggest mouth in the world as well. About 100 people can stay inside it. But it doesn’t eat people! 34 fact, the biggest thing it can eat is the size of an apple. The giraffe is 35 (small) than the blue whale but it is also a record breaker. It’s the tallest living land animal. It has the longest neck, about 2 meters long, 36 it has the longest legs, about 1.8 meters long. Drinking is difficult for it, but 37 (eat) from the top of trees is easy! And its tongue (舌头) is 50 cm long! The most dangerous animal in the world isn’t a lion or a bear. It’s 38 insect (昆虫)! Mosquitoes (蚊子) are one of the most dangerous 39 (animal) in the world. Mosquitoes with malaria (疟疾)   40 (kill) over one million people every year. After that, another most dangerous animal is the venomous (分泌毒液的) snake. The snakes kill 50,000 to 125,000 people a year. 试卷第1页，共3页 试卷第1页，共3页 学科网（北京）股份有限公司 $ Unit 5 Saving animals in danger It作形式主语和adj+enough+to+v （时间：40分钟，满分：60分） 一、单项选择(本大题共20小题，每小题1分，共20分) 1．It is ________ of Tom to be late for school again. A．careless B．important C．difficult D．necessary 【答案】A 【详解】句意：汤姆又上学迟到了，真是粗心。 careless粗心的；important重要的；difficult困难的；necessary必要的。根据“to be late for school again”可知再次迟到是不好的行为，体现了汤姆的粗心，符合语境。 2．It is clever ________ the girl ________ find the way home by herself. A．for; to B．of; to C．for; for D．of; of 【答案】B 【详解】句意：这个女孩自己找到回家的路是很聪明的。 固定句型“It is+adj.+of+sb.+to do sth.”中，当形容词表示人的性格品质（如 clever）时用介词of；动词不定式作真正主语用to。 3．It is necessary ________ students ________ get up early every day. A．of; to B．for; to C．of; for D．for; for 【答案】B 【详解】句意：每天早起对学生们来说是必要的。 of属于；to朝，到；for为了。根据“It is necessary…students…get up early every day.”可知，本句为固定句型“It is+adj.+for/of+sb.+to do sth.”。当形容词描述人的性格品质时用of，描述事物性质时用for，necessary意为“必要的”，描述事物性质，故第一空填for；句型中真正的主语是动词不定式，故第二空填to。应填for；to。 4．It is wrong ________ you ________ laugh at others. A．for; to B．of; to C．for; for D．of; of 【答案】B 【详解】句意：你嘲笑别人是错误的。 此处为“It is+形容词+of/for+sb+to do sth.”固定句型。当形容词表示人的性格、品质（如wrong，kind，clever等）时，用介词of；当形容词表示事物的性质（如hard，easy，important等）时，用介词for。本句中“wrong”是对人的行为评价，故第一空用of；第二空是不定式作真正的主语，用to。 5．The box is ________ heavy ________ the little girl to carry. A．too; to B．enough; to C．too; for D．enough; for 【答案】C 【详解】句意：这个箱子太重了，这个小女孩搬不动。 too...to...太……而不能……；enough...to...足够……去做……；too....for...对……来说太……；enough...for...对……来说足够……。根据“The box is...heavy...the little girl to carry.”和结构可知，此处表示“对这个小女孩来说太重而搬不动”，应填too; for。 6．It is meaningful ________ us ________ take part in the volunteer activities. A．for; to B．of; to C．for; for D．of; of 【答案】A 【详解】句意：参加志愿者活动对我们来说是有意义的。 形容词 meaningful 描述事物的性质，而非人的性格特点，故第一空用for；不定式作真正主语，第二空用to。故选A。 7．The boy is ________ to reach the apple on the tree. A．enough tall B．tall enough C．too tall D．tall too 【答案】B 【详解】句意：这个男孩足够高，能够到树上的苹果。 enough 修饰形容词或副词时，要后置，结构为“形容词 + enough”。根据语境男孩能够到苹果，说明身高足够，且enough需放在tall之后。 8．It’s patient ________ you ________ wait for me for so long. A．for; to B．of; to C．for; wait D．of; wait 【答案】B 【详解】句意：你等了我这么久，真有耐心。 It’s + adj. + of sb. to do sth.，该句型用于描述人的品质、性格。形容词patient意为“有耐心的”，用来修饰人的品质性格，介词应用of；该句型中真正的主语是动词不定式，第二空应用to。 9．—It’s generous _________ you to offer free meals to the homeless.   —I think it’s meaningful _________ us to do something for others. A．of; for B．for; of C．of; to D．to; for 【答案】A 【详解】句意：你主动给无家可归的人提供免费餐食，真是太慷慨了。我觉得，能为别人做点事，对我们来说也是很有意义的。 本题考查的是It is+adj+of/for+sb+to do sth. 这个经典句型中介词的选择。当形容词是用来评价人的品格、性格或行为性质时，用of。当形容词是用来描述事物本身的性质、特征或对某人的影响时，用for。generous “慷慨的，大方的”，表人品。meaningful有意义的，通常用来形容某件事，某个活动或某段经历具有价值或目的。故选A。 10．It’s necessary _________ a second language well if you want to work abroad. A．learn B．learning C．to learn D．learned 【答案】C 【详解】句意：如果你想出国工作，学好一门外语是必要的。 “It’s +形容词 + to do sth.”为固定句型，其中it为形式主语，真正主语是后面的不定式短语，to learn符合语境。 11．_________ is important for everyone to protect the environment. A．This B．That C．It D．There 【答案】C 【详解】句意：对每个人来说，保护环境是很重要的。 This这个；That那个；It它；There那儿。在固定句型It is+形容词 + for sb. to do sth.中，只有It可作形式主语，其他选项均不能充当形式主语，其中This和That为指示代词，There为副词。该句型中需用It作形式主语，真正的主语是后面的不定式to protect the environment，故用It。 12．The girl is ________ to go to school. A．enough old B．old enough C．too old D．so old 【答案】B 【详解】句意：这个女孩年龄足够大可以去上学了。 enough修饰形容词时须放在形容词之后，old enough足够大；too old 太大，too +adj.+to do sth.表示“太……而不能”；so old如此大。本句固定结构“adj. + enough + to do sth.”表示“足够……去做某事”。 13．It is very kind ________ you to volunteer at the wildlife rescue center every weekend. A．of B．for C．to D．with 【答案】A 【详解】句意：每个周末去野生动物救援中心做志愿者，你真是太善良了。 of……的；for对于；to向；with和。此处是固定句型“It is+adj+of/for+sb+to do sth.”，当形容词表示人的性格、品质（如kind, nice等）时用介词of；当形容词表示事物的性质（如hard, easy等）时用介词for。本句中“kind”意为“善良的”，是修饰人的品质，应填of。 14．The rescue team worked day and night, and finally the injured crane was ________ to fly back to the wild. A．enough strong B．strongly enough C．strong enough D．enough strongly 【答案】C 【详解】句意：救援队日夜奋战，最终这只受伤的鹤足够强壮，可以飞回野外了。 be动词was后接形容词作表语，且enough修饰形容词时需后置，用strong enough。 15．—Why didn’t you stop the boy from throwing rocks at the duck? —Because I was not ________ to argue with him at that time. A．enough brave B．brave enough C．enough bravely D．bravely enough 【答案】B 【详解】句意：——你为什么没有阻止那个男孩向鸭子扔石头？——因为那时我没有足够勇敢去和他争论。   根据语法规则，enough修饰形容词时需后置，可排除A、C；句中“was”是系动词，后接形容词作表语，brave是形容词，bravely是副词，因此排除D。brave enough符合语法及语境。 16．The box is ________ heavy for the little boy ________ carry. A．too; to B．enough; to C．so; that D．such; that 【答案】A 【详解】句意：这个箱子对这个小男孩来说太重了而不能搬动。 too...to... “太……而不能……”；enough修饰形容词时需放在形容词之后；so/such...that...，that后接从句。第一空后“heavy”是形容词且第二空后接动词原形“carry”，所以应用“too... to...”结构，表达这个箱子对这个小男孩来说太重了而不能搬动。 17．The boy was ________ brave enough to stop the hunter from killing the bird. A．not B．no C．never D．don't 【答案】A 【详解】句意：这个男孩不够勇敢，没能阻止猎人猎杀那只鸟。 not不（副词，用于否定形容词或副词）；no没有（不能直接修饰形容词）；never从不（副词，表示频率）；don’t不（助动词，用于否定谓语动词）。“brave enough”为形容词短语，否定时应在brave前加not，构成“not brave enough”，意为“不够勇敢”，应填not。 18．It is wrong ________ people to buy fur coats made from endangered wild animals. A．of B．for C．to D．with 【答案】A 【详解】句意：人们购买由濒危野生动物制成的皮草大衣是错误的。 of属于……的；for为了；to到；with和。分析句子可知，该句是“It is+形容词+介词 +sb.+to do sth.”句型，空格前“wrong”是表示人的行为特征，所以介词用of。 19．It was extremely cruel ________ the poachers to kill the mother elephant for its tusks. A．of B．for C．to D．with 【答案】A 【详解】句意：偷猎者为了象牙杀死母象是极其残忍的。   of……的；for对于；to向；with和。在“It is + adj. + of/for sb. to do sth.”句型中，当形容词描述人的品质、性格特征（如cruel）时，用介词of；若形容词描述事物本身性质，则用for。本句中“cruel”是修饰偷猎者的品质，故用of。 20．It is not easy ________ many animal species to survive in the wild. A．of B．for C．to D．with 【答案】B 【详解】句意：对于许多动物种类来说，在野外生存是不容易的。 of……的；for对于；to到；with和……一起。“It is+形容词+for sb./sth. to do sth.”是固定句型，表示“对某人/某物来说做某事是……的”，其中it是形式主语，真正的主语是后面的动词不定式。 二、完成句子(本大题共10小题，每小题2分，共20分) 21．给老人让座是正确的。 It is right ________ ________ ________ seats to the elderly. 【答案】 to give up 【详解】原句中“让座”是关键词，表示“让座”的动词短语是give up seats to sb.。It is right to do sth.意为“做某事是正确的”，it作形式主语，动词不定式to give up seats作真正的主语。 22．你犯这样的错误真是太粗心了。 It is really careless ________ you ________ ________ such a mistake. 【答案】 of to make 【详解】原句中“太粗心”描述的是做出“犯这样的错误”这一行为的人的特征，“It is +形容词+of sb. to do sth.”是一个常用句型，用于表示某人做某事具有某种品质或特征，其中形容词是用来描述人的性格、品质等方面的。在这个句子中，“careless（粗心的）”是描述人的品质的形容词，“make such a mistake（犯这样的错误）”是具体的行为动作，所以这里用“of”引出做出行为的人“you”，用“to make”表示具体的行为。 23．对孩子们来说在河里游泳是危险的。 It is dangerous ________ children ________ ________ in the river. 【答案】 for to swim 【详解】It is +adj. +for sb+to do sth 意为“对于某人来说，做某事是……的”。句中It是形式主语，形容词dangerous描述的是 “在河里游泳” 这件事的危险性，因此用for sb. 引出动作对象，①处填for； 句子的真正主语是“游泳”，需要用不定式形式to swim，因此②处填不定式符号 to，③处填动词原形swim。 24．你能帮我拎这个重箱子，真是太善良了。 It is very kind ________ you ________ ________ me carry the heavy box. 【答案】 of to help 【详解】对照中英文可知，缺少“帮助”和“对……来说”。help是动词，意为“帮助”。本句为“It is + adj. + of sb. to do sth.”句型，形容词kind描述人的品质，应用介词of，形容词后需接不定式to do。 25．对我们来说每天锻炼很重要。 It is important ________ us ________ ________ exercise every day. 【答案】 for to take 【详解】根据句型It is important for sb. to do sth.意为“对某人来说做某事很重要”，for引出对象，us是人称代词宾格，后接不定式表示具体的动作；take exercise“做运动”。 26．He is generous to share his food with us.   It’s ________ ________ ________ to share his food with us. 【答案】 generous of him 【详解】句意：他很慷慨，和我们分享他的食物。原句可转换为固定句型“It’s + 形容词 + of sb. + to do sth.”，表示 “某人做某事是……的”。此处形容词为generous，由原句中的“He”可知此处sb.为him。故填generous；of；him。 27．在生活中他足够勇敢去面对各种困难。 In life, he ________ to face all kinds of difficulties. 【答案】is brave enough 【详解】原句中“足够勇敢”是关键词，对应英文结构“be + 形容词 + enough to do sth.”。主语“he”为第三人称单数，且描述一般情况，故用一般现在时“is”。“勇敢”译为“brave”，“足够”放在形容词后，即“brave enough”。 28．Liu Ming left his homework at home again. He was careless. (合并为一句)   It ________ ________ ________ Liu Ming to leave his homework at home again. 【答案】 was careless of 【详解】句意：刘明又把作业落在家里了。他是粗心的。题目要求将两个句子合并为一句，表达“某人做某事是……的”这一含义，常用句型“It is/was + 形容词 + of/for sb. to do sth.”。该句中形容词careless描述人的特质，介词用of。原句时态为一般过去时，故be动词用was。 29．每天练习说英语对我们来说很有必要。 →________ ________ for us to practice speaking English every day. 【答案】 It’s necessary 【详解】原句中“很有必要”是关键词，表示“很有必要”的短语是It’s necessary。本句描述一般情况，用一般现在时即可。 30．这个医生足够耐心，解答了所有问题。(完成译句) The doctor is ________ ________ to answer all the questions. 【答案】 patient enough 【详解】原句中“足够耐心”是关键词组，“耐心”对应的英文单词是“patient”，“足够”对应的英文单词是“enough”。在英语中，“enough”修饰形容词或副词时要后置，所以“足够耐心”应表达为“patient enough”。 三、短文填空(本大题共10小题，每小题2分，共20分) 阅读下面短文，在空白处填入一个适当的单词或括号内单词的正确形式。 There are world records at the Olympic Games. But what are the world 31 (record) in the animal kingdom (王国)? The 32 (large) and heaviest animal on the earth is the blue whale. It weighs (重) between 110 and 120 tons. 33 (it) heart is the size of a small car. It has the biggest mouth in the world as well. About 100 people can stay inside it. But it doesn’t eat people! 34 fact, the biggest thing it can eat is the size of an apple. The giraffe is 35 (small) than the blue whale but it is also a record breaker. It’s the tallest living land animal. It has the longest neck, about 2 meters long, 36 it has the longest legs, about 1.8 meters long. Drinking is difficult for it, but 37 (eat) from the top of trees is easy! And its tongue (舌头) is 50 cm long! The most dangerous animal in the world isn’t a lion or a bear. It’s 38 insect (昆虫)! Mosquitoes (蚊子) are one of the most dangerous 39 (animal) in the world. Mosquitoes with malaria (疟疾)   40 (kill) over one million people every year. After that, another most dangerous animal is the venomous (分泌毒液的) snake. The snakes kill 50,000 to 125,000 people a year. 【答案】 31．records 32．largest 33．Its 34．In 35．smaller 36．and 37．eating 38．an 39．animals 40．kill 【导语】本文主要介绍了动物王国中的一些世界纪录，包括蓝鲸、长颈鹿以及世界上最危险的动物等。 31．句意：但是动物王国里的世界纪录是什么呢？根据“There are world records at the Olympic Games. But what are the world...(record) in the animal kingdom (王国)?”可知，此处指动物王国里的世界纪录，record表示“纪录”，为可数名词，根据are可知，此处用复数形式。故填records。 32．句意：地球上最大最重的动物是蓝鲸。根据“The...(large) and heaviest animal on the earth is the blue whale.”可知，此处指地球上最大最重的动物，and连接并列成分，故此处用形容词最高级largest“最大的”。故填largest。 33．句意：它的心脏有一辆小汽车那么大。根据“…(it) heart is the size of a small car.”可知，此处指蓝鲸的心脏，用形容词性物主代词its“它的”修饰名词heart，句首首字母大写。故填Its。 34．句意：事实上，它能吃的最大的东西只有苹果那么大。根据“...fact, the biggest thing it can eat is the size of an apple.”可知，此处是固定短语in fact“事实上”，句首首字母大写。故填In。 35．句意：长颈鹿比蓝鲸小，但它也是一名破纪录者。根据“The giraffe is…(small) than the blue whale but it is also a record breaker.”可知，此处是比较级，small的比较级是smaller“更小的”。故填smaller。 36．句意：它的脖子最长，约2米长，腿也最长，约1.8米长。根据“It has the longest neck, about 2 meters long,…it has the longest legs, about 1.8 meters long.”可知，前后两句是并列关系，用and连接。故填and。 37．句意：喝水对它来说很难，但从树顶吃东西很容易！根据“Drinking is difficult for it, but…(eat) from the top of trees is easy!”可知，此处作主语，用动名词形式eating“吃”。故填eating。 38．句意：它是一种昆虫！根据“It’s…insect (昆虫)!”可知，insect是可数名词单数，此处表示泛指，且insect以元音音素开头，用不定冠词an。故填an。 39．句意：蚊子是世界上最危险的动物之一。根据“Mosquitoes (蚊子) are one of the most dangerous…(animal) in the world.”可知，one of the+形容词最高级+名词复数“最……之一”，animal的复数形式是animals“动物”。故填animals。 40．句意：携带疟疾的蚊子每年杀死超过一百万人。根据“Mosquitoes with malaria (疟疾)…(kill) over one million people every year.”可知，此处描述客观事实，用一般现在时，主语是Mosquitoes，谓语动词用原形kill“杀死”。故填kill。 试卷第1页，共3页 试卷第1页，共3页 学科网（北京）股份有限公司 $