11. be 动词(am/is/are) 主语 be 动词(原形) be 动词(过去式) I am was He/she/it is was We/you/they are were 口诀:我用 am, 你用 are,is 用在他她它,所有复数全用 are ①肯定和否定句 I am (not) from London. He is(not) a teacher. She is(not) in the dining room. My hair is(not) long. Her eyes are(not) small. ②一般疑问句 Am I a Chinese?——Yes, you are. /No, you aren’t. Is the cat fat? ——Yes, it is. /No, it isn’t. Are they American?—— Yes, they are. /No, they aren’t. 表示疑问,一般回答只有两种可能 Yes 或 No,句中没有疑问词。 如何将一个肯定的陈述句改为否定句: 1、看句中有无 be 动词,如有,把 be 动词提到句首即可。 2、看句中有无情态动词,如有,把情态动词提到句首即可。 3、如上述二者都没有,就应把助动提到句首。