英语中的时态一共有八种，它们是：一般现在时、现在进行时、一般过去时、现在完成时、一般将来时、过去进行时、过去完成时、过去将来时。
今天我们所要讲的就是第一种： 一般现在时——表示一般性，经常性的动作或一般性事实。
1、含有be动词的句子
He is a teacher.
The girl is very beautiful.
Tim and Jack are students.
★变疑问句将be动词移到句首
Is he a teacher?
Is the girl very beautiful?
Are Tim and Jack students?
★变否定句在be动词后面加not
He is not a teacher.
The girl is not very beautiful.
Tim and Jack are not students.
★肯定回答及否定回答
Yes, he is. / No, he is not.
Yes, she is. / No, she is not.
Yes, they are. / No, they are not.
2、不含有be动词的句子，即含有一般动词的句子。
(1)第三人称单数及单数名词
He likes books.
She likes him.
The dog likes bones.
★变疑问句在句首加does, 动词变为原型
Does he like books?
Does she like him?
Does the dog like bones?
★变否定句在主语及动词之间加doesn't, 动词变为原型，原句中的动词不再有第三人称变化。
He doesn't like books.
She doesn't like him.
The dog doesn't like bones.
★肯定回答及否定回答：
Yes, he does. / No, he doesn't.
Yes, she does. / No, she doesn't
Yes, it does. / No, it doesn't.
注意：第三人称单数形式一般在动词后面加S，不要和名词复数混淆，变否定句或疑问句时名词复数没有任何变化。
(2)其他人称及复数名词
I want to have a bath.
We have some meat.
The students like smart teachers.
★变疑问句在句首加do
Do you want to have a bath?
Do we have any meat?
Do the students like smart teachers?
★变否定句在主语和动词之间加don't.
You don't want to have a bath.
We don't have any meat.
The students don't like smart teachers.
★肯定回答及否定回答
Yes, I do. / No, I don't.
Yes, we do. / No, we don't
Yes, they do. / No, they don't.