Unit 1 Section Ⅳ Grammar-【金版新学案】2024-2025学年新教材高一英语必修第二册同步课堂高效讲义教师用书word（外研版2019）
Section Ⅳ Grammar
情态动词(Ⅰ)
语法串烧 | 我的发现 |
As a senior one student, Li Qing is able to adjust himself to the new school life. In classes, he has to focus himself on his teachers, or he can't grasp what his teachers have taught. Meanwhile, his teachers often tell him that he had better balance his study and play. He needn't stay up to do his homework. However, I dare say he is going to challenge himself to more subjects in one term. | ①黑体词汇都是情态动词，它们后面都接动词原形。 ②情态动词一般无人称和数的变化。can和dare有时态变化，be able to和have to有人称和时态的变化。 ③构成否定句时，not放在情态动词后面。 |
1．can与be able to
(1)can只有现在时和过去时(could)，而be able to则有更多的时态变化，在将来时、完成时和非谓语动词中只能用be able to。
This time I failed in the exam，but I'll be able to pass the exam next time.
这次我考试不及格，但下次考试我能及格。(将来时)
(2)can一般指自身具有的能力，而be able to则表示经过一段时间的努力后所具有的能力，相当于manage to do或succeed in doing。
I can/am able to speak both English and French.
我会说英语和法语。
[名师点津]
现在时can与be able to没有区别，但是在过去时中二者意义不同。
All the people could escape from the burning hotel last night.
昨晚所有的人都有能力从燃烧的旅馆里逃脱出来。(有这种能力，但不一定做到)
All the people were able to escape from the burning hotel last night.
昨晚所有的人都从燃烧的旅馆里逃脱出来了。(成功做到了)
(3)在否定结构中was/were able to与could没有区别。
学科网（北京）股份有限公司
She ran fast but she couldn't/wasn't able to catch the bus.
她跑得很快可还是没能赶上公交车。
(4)can/could表示请求别人做某事，意为“能，可以”。
—Can/Could I come to see you tomorrow?
—Yes，you can.
——我明天能来看你吗？
——可以。
(5)can/could表示惊讶，常用在否定句和疑问句中。
How could you do such a silly thing？(表示惊讶)
你怎么能做那样的蠢事呢？
◎巧学活用1——选词填空(can/could/be able to)
①If you have a good sleep，you will be_able_to work out this problem.
学生用书第23页 |
②When I was young，I could climb any tree in the woods.
2．need的用法
(1)need作情态动词时，后跟动词原形，表示“需要，有必要”，无人称和数的变化，多用于疑问句、否定句或条件句中。其否定形式是在其后直接加not，疑问形式是直接将need提到主语前。由need构成的一般疑问句，其肯定回答用must或have to。否定回答常用needn't。
—Need I finish the work today?
—Yes，you must/have to./No，you needn't.
——我需要今天干完这项工作吗？
——是的，你必须干完。/不用，你不必干完。
There's plenty of time.You needn't drive so fast.
时间很充足，你不必开这么快。
(2)作实义动词
need作实义动词时，后可接名词、动词ing 形式、动词不定式等，有人称、时态和数的变化，其否定形式、疑问形式都要通过助动词do构成。物作主语时need后跟doing或to be done。
学科网（北京）股份有限公司
There are always people who need help from others.
总会有人需要他人的帮助。
He didn't need to set off so early.
他不必那么早出发。
Do I need to leave my telephone number and address?
我有必要把电话号码和地址留下吗？
The bike needs repairing.
＝The bike needs to be repaired.
这辆自行车需要修理。
◎巧学活用2——用所给单词的适当形式填空
①I love the weekend, because I needn't get(get) up early on Saturdays and Sundays.
②I need to_collect(collect) the parcel before leaving for England.
3．must与have to
(1)must表示“必须”，语气强烈。have to表示“不得不”，意义与must相近，但又有所区别。must表示说话人的主观看法，have to则强调客观需要；must只有一种形式，而have to有人称、时态等方面的变化。
—Shall I inform him of the change of the schedule right now?
—I am afraid you must，in case he comes late for the meeting.
——日程改了，我该马上通知他吗？
——我想你必须(通知他)，以免他开会迟到。
I have to go now，because my mother is in hospital.
我现在不得不走了，因为我母亲住院了。
(2)must表示推测，意为“一定”，用于肯定句。must have done是对过去事情的推测。
Someone must have used my umbrella yesterday. I found it wet.
昨天一定有人用了我的雨伞，我发现它湿了。
(3)must含有感情色彩，意为“偏要，非要……不可”。
If you must go，at least wait until the storm is over.
如果你非要走，至少要等到暴风雨停止。
学科网（北京）股份有限公司