动词的单复数
第三人称单数做主语时，一般在动词词尾加S。第一人称，第二人称单数和复数做主语时，动词用原型。比如：
The cat makes friend with the dog. I go to school alone.
猫和狗做朋友。我一个人去上学。
做一做：圈出括号中的正确的单词完成句子。
1.Two cats ( play, plays) on the stairs.
2. A girl (see, sees) a tree.
3.They (eat, eats)some friut.
助动词
助动词是语法功能词，自身没有意义，不可单独使用，它协助实义动词构成谓语动词。
实义动词的一般现在时的否定句和疑问句借助于助动词do或does来构成，
否定句中：当主语时第三人称单数时，就用does来帮助，后接动词原形。
He has a knife.-------He doesn’t have a knife.
当主语时第一，二人称或是第三人称复数时，就用do 来帮助。
They like apples.--------They don’t like apples.
由do或does构成的疑问句句式为：
1.一般疑问句的句式：
Do + I /We/ You/ They + 动词原形…..？
Does + he /she/ it + 动词原形….？
回答语：Yes , I /We/ You/ They do.
No, I /We/ You/ They don’t.
Yes, he /she/ it does.
No, he /she/ it doesn’t.
如：------Do they any eggs?---- Yes, they do.
2.特殊疑问句的句式：
特殊疑问词（如：What/ Where/ When….）+ 一般疑问句？
Where does she live? ( 她住在哪里？)
练习题：
一．e.g My sister likes apples, but he doesn’t like pears. ×∨
1. She_____ ______, but she ______ ______ ______.
2. He______ ______, but she _______ ______ ______.
3.Candy ______ ______,but she______ ______ _______.
4._____ Mr. Zhang______ _______?
No, he ______. But he _______ ______.
5.______ your best friend ______ _______?
No, he ______. But he _______ _______.
二．根据提示做出回答。
1.Do you like cats？（作肯定回答）
Yes, ________________.
2.Does your mother like kangroos? (作否定回答)
No, ________________.
3.I like chips.( 改I 为She)
______ ________ chips.
4.He likes rabbits and dogs. ( 改She 为I)
______ ________ rabbits and dogs.
5.Candy does her homework every day. (改为否定句)
Linda ______ ______ her homework every day.