be 动词
先看用法说明，再到底部练习。
一、现在时
口诀：我用 am，你用 are，is 跟着他她它；单数 is，复数 are。
I 用 am
I am a student.
我是一名学生。
you / we / they / 复数主语用 are
Tom and I are friends.
汤姆和我是朋友。
he / she / it / 单数主语用 is
She is my sister.
她是我的姐姐。
不可数名词作主语用 is
The news is exciting.
这条消息令人兴奋。
二、过去时
am / is → was
I was at home yesterday.
我昨天在家。
are → were
They were late last night.
他们昨晚迟到了。
标志词：yesterday, last night, last week, …ago
He was ill two days ago.
他两天前生病了。
三、There be 句型与就近原则
There is + 单数 / 不可数名词
There is some milk in the cup.
杯子里有一些牛奶。
There are + 复数名词
There are two books on the desk.
桌上有两本书。
多个名词并列：be 与最近的名词一致
There is a pen and two books on the desk.
桌上有一支笔和两本书。
either…or / neither…nor：就近原则
Neither he nor I am late.
他和我都没有迟到。
The number of + 复数名词作主语，用 is
The number of students is 40.
学生的数量是 40。
四、疑问与否定
一般疑问句：be 动词提到主语前
Are you ready?
你准备好了吗？
否定句：be 动词后加 not
She is not (isn't) here.
她不在这里。
✏️ 开始练习
中译英
句子含现在时与过去时，附关键词提示；时间短语放句首或句尾都算对。