1.肯定句：是指用肯定的语气来陈述的句子，如：I'm a student. She is a doctor. He works in a hospital.

There are four fans in our classroom. He will eat lunch at 12:00. I watched TV yesterday evening.

2,否定句：含有否定词或表示否定意义词的句子，如：I'm not a student. She is not (isn't) a doctor.

He does not (doesn't) work in a hospital. There are not (aren't) four fans in our classroom.

He will not (won't) eat lunch at 12:00. I did not (didn't) watch TV yesterday evening.

☆注意☆ 小结：否定句主要是在肯定句的基础上加上了否定词 "not".有动词be的句子则"not"加在be后面，可缩写成"isn't,aren't",但am not 一般都分开写。没有动词be的句子则要先在主要动词的前面加上一个助动词(do,does,did),然后在它后面加上"not",你也可以把它们缩写在一起如"don't , doesn't , didn't ).这三个助动词要根据人称和时态来选择，其中"does“只用于一般现在时主语是第三人称单数的情况，而”did“只用于一般过去时，不论主语是什么人称和数，都用”did" .

3,一般疑问句：是指询问事实的句子，此类句子必须用"yes",或"no"来回答。

如：Are you a student Yes, I am / No, I'm not.

Is she a doctor Yes, she is. / No, she isn't.

Does he work in a hospital Yes, he does. / No, he doesn't.

Are there four fans in our classroom Yes, there are. / No, there aren't.

Are you going to buy a comic book tonight Yes, I am. / No, I am not. (Yes, we are. / No, we aren't.)

Will he eat lunch at 12:00 Yes, I will. / No, I will not(won't).

Are they swimming Yes, they are. / No, they aren't.

Did you watch TV yesterday evening Yes, I did. / No, I didn't.

☆注意☆ 小结：一般疑问句是在肯定句的基础上，

①把动词be调到首位，其他照写，末尾标点符号变成问号即可。

②没有动词be的句子则要在句首加上一个助动词(do,does,did)再把紧跟在后面的动词变回原形，末尾标点符号变成问号即可。

这三个助动词也要根据人称和时态来选择，其中"does“只用于一般现在时主语是第三人称单数的情况，而”did“只用于一般过去时，不论主语是什么人称和数，都用”did" .一般疑问句有个重要的原则就是问和答要一致，即问句里的第一个单词(助动词)和简略答句里的这个词是一致的。

今天就和大家就分享到这，祝愿同学们用辛勤的汗水去收获美好的未来吧！