祈使句是表示请求、命令、劝告、祝愿或建议的句子。祈使句的主语一般为第二人称，但往往省去不用。同学们在学习祈使句时应注意以下几点：
一、祈使句谓语用何动词形式
英语祈使句的谓语总是用动词原形。
如：
Be quiet!
别说话!
Come earlier next time.
下次早点来。
Have a good time.
愿你玩得痛快。
Go and tell her.
去告诉她吧。
注：有时为了加强语气，可在动词前加do。
如：
Do be careful. 务请小心。
Do come on time. 务必请准时来。
二、肯定祈使句如何变成否定祈使句
祈使句否定式的构成方法是在动词原形前加don’t：
Don’t be late. 不要迟到。
Don’t speak so loud. 别这么大声说话。
三、与please连用以使语气委婉
为使语气委婉，通常将祈使句与please连用。Please可用于祈使句的句首(其后通常不用逗号)或句末(其前通常用逗号)。如：
Please try to be quiet. 请设法保持安静。
Please repeat what you’ve just said. 请把你刚才说的话重复一遍。
四、关于以let开头的祈使句
Let me show you how to do it. 我来告诉你怎样做。
Let every man do his best. 让每个人人尽其才。
注意：
1. 这类祈使句的否定式有两种形式如：
Let’s not hurry. / Don’t let’s hurry. 我们不要太急。
2. let后用作宾语补足语的动词要用原形，不能用带to的不定式。
五、祈使句的反意疑问句形式
1. 在通常情况下，若陈述部分为祈使句，反意疑问句通常用will you, won’t you, would you
Turn on the TV, will you? 把电视打开，好吗?
Tell me the truth, won’t you? 告诉我实话，好吗?
注：若陈述部分为否定式，则反意疑问句部分只用will you。如：
Don’t forget to post the letter, will you? 请别忘了寄信。
2. 若陈述部分为以 let开头的祈使句，则要分两种情况：
(1) 表示请求时，用will you?
Let us know your address, will you? 把你的地址告诉我们吧，好吗?
(2) 表示建议时，用shall we?
Let’s all sit under this tree, shall we? 咱们都坐在这棵树下，好不好？
Practice today:
Error Correction
1．A majority of the reports received from people claiming
to have seen the lengendaiy Loch Ness monster have
proven to be mistakes, misconceptions, or tricked. ___________
2. Your semester grade is based not only on how well you
do on each test, but also how you participate in class. ___________
3. Modern sience was born when Galileo began trying to explain
how things happen and thus originating the method of controlled __________
experiment which now forms the basis of scientific investigation
4. Restrict your self to one or two pages, and listing ___________
any publications or referees on a separate sheet.
5. The House proposal would have barred the federal
government from demanding library records, read lists, __________
book customer lists and other material in terrorism and
intelligence investigations.
答案与解析：
1. tricked -> tricks
并列连词or连接三项成分。前两项均为名词，故tricked应改为名词tricks与前面的mistakes和misconceptions平行。
2. how前加on
3. originating -> originated
And后面的thus说明并列句的第二部分是和前面的began对应，而非与trying对应。
4. listing -> list
这句是祈使句，list与前面的restrict并列。
5. read -> reading
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