助动词be 的用法?最好带例句!

助动词be 的用法?最好带例句!
助动词be 的用法?最好带例句!

助动词be 的用法?最好带例句!
1、be动词的用法.
be\x05am / is\x05are\x05现在时
was\x05were\x05过去时
单数\x05复数\x05
英语中,be动词选用单数还是复数,要由主语来定,主语是单数,就用单数,反之用复数.
◆ 句中含有be动词时：
肯定句：主语＋be ＋ 其他
否定句：主语＋ be ＋ not ＋ 其他
一般疑问句：Be ＋主语＋其他
特殊疑问句：疑问词（what / who / when / where） ＋ be ＋主语 ＋ 其他
I am a teacher.You are right.
She is 16 years old.My father is at home.
The students are playing games.My teacher was ill yesterday.
There is a picture on the wall.
There are two books on the table.

be doing. He is singing