Unit 25 陈述句
陈述句是用来说明一个事实或表明说话人的看法。陈述句的末尾用句号，朗读时一般用降调。陈述句分为肯定句式和否定句式。陈述句要用正常语序。
语法讲解
肯定句
1．主语＋系动词＋表语
He is a teacher. 他是名老师。
2．主语＋实义动词＋其他
Lily dances well. 莉莉跳舞跳得很好。
3．主语＋情态动词＋动词原形＋其他
Mary can speak Japanese. 玛丽会说日语。
4．主语＋助动词will/have/has/had ＋动词原形／过去分词＋其他
They will go abroad next year. 他们明年要出国。
否定句
1．主语＋be 动词＋not ＋其他
These are not my pencils. 这些不是我的铅笔。
2．主语＋do/does/did ＋not ＋动词原形＋其他
I don't like singing. 我不喜欢唱歌。
3．主语＋助动词will/have/has/had＋not ＋动词原形／过去分词＋其他
I won't go to work tomorrow. 我明天不去上班。
4．主语＋情态动词＋not ＋动词原形＋其他
She can't play the piano well. 她钢琴弹得不好。
由肯定句变否定句的方法
1．找原句的动词。若动词为等，直接在动词后加am ，is ，are ，can ，must ，will 等，直接在动词后加not 变否定。若动词为want ，like 等实义动词，要借助助动词don't 或doesn't 放在原句动词之前变否定句（原句动词为单三形式用doesn't ，其他形式用don't ）。
2．原句其他单词位置不变。
I am a teacher. I am not a teacher. 我是一名教师。我不是一名教师。
Mary likes apples. Mary doesn't like apples. 玛丽喜欢苹果。玛丽不喜欢苹果。
巧学妙记
have在表示“有”时，其否定形式有两种，一种是在后面加not，一种是利用do的形式。
I haven't any time to play football.
I don't have any spare time to play football.
我没有时间踢足球。
语法练习
一、连词成句，注意大小写和标点符号。
1．plays/he/basketball/.
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2．he/runs/./fast
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3．the/./train/at seven/leaves
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4．is/Mary/nurse/./a
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5．./she/piano/the/play/can
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二、读一读，选择单词将句子补充完整。
1．My father is a __________. A．swim
2．He can __________ well. B．terrible
3．I have been to __________. C．doctor
4．The soup tastes __________. D．tomorrow
5．We won't go to the park __________. E．America
三、把下列句子变成否定句。
1．She is a teacher.
2．I have a baseball.
3．I have been to Japan.
4．We like to play computer games.
5．He can skate.
答案
一、1．He plays basketball.
2．He runs fast.
3．The train leaves at seven.
4．Mary is a nurse.
5．She can play the piano.
二、1．C
2．A
3．E
4．B
5．D
三、1．She isn't a teacher.
2．I don't have a baseball.
3．I haven't been to Japan.
4．We don't like to play computer games.
5．He can't skate.
