be 动词是英语句子的骨架，写句子第一件事就是选 am、is 还是 are。小学生最常犯的错是 I is、He are，以及 there be 句型里忘了就近原则。这篇把规则压缩成一句口诀加一张表。
be 动词的搭配规则
| 主语 | be 动词 | 例句 |
|---|---|---|
| I | am | I am a student. |
| he / she / it 及单数名词 | is | The cat is fat. |
| you / we / they 及复数名词 | are | They are my friends. |
| 缩写形式 | I am = I'm；is not = isn't；are not = aren't | She's a teacher. He isn't late. |
口诀：我用 am，你用 are，is 跟着他她它；单数 is，复数 are。变疑问把 be 提到句首，变否定在 be 后加 not。
there be 句型：表达「某地有某物」
- 基本结构：There is / are + 某物 + 某地。如 There is a book on the desk.
- 就近原则：后面最近的名词是单数用 is，是复数用 are。There is a pen and two books on the desk.
- 变否定：There isn't any milk in the glass.（some 常改 any）
- 变疑问：Is there a park near your home? 肯定回答 Yes, there is.
易错点：there be 与 have 各管一摊
there be 说「某地存在某物」，have 说「某人拥有某物」。There is a TV in my room（房间里有一台电视）不能写成 There has a TV；I have a TV（我有一台电视）也不能写成 I am have。判断方法：主语是地点或 there 用 there be，主语是人用 have 或 has。考题常拿 There 后面接 has 制造陷阱，见到 there be 结构就坚决排除 have。