F-01
am / is / are
be 动词三兄弟💡 概念 Concept
The verb be changes with the subject: I am, he / she / it is, you / we / they are. In speech and writing we often shorten them: I'm, she's, they're.be 动词随主语变化：I am，he / she / it is，you / we / they are。口语和书写中常缩写：I'm、she's、they're。
📐 规则 Rules
I → am
I am a student. I'm from China.
我是学生。我来自中国。
he / she / it → is
She is my friend. It is a cat.
她是我的朋友。它是一只猫。
you / we / they → are
You are right. We are classmates.
你是对的。我们是同学。
缩写
I'm · you're · he's · she's · it's · we're · they're
I'm、you're、he's、she's、it's、we're、they're
✏️ 例句 Examples
I am very happy today.
我今天很开心。
She is my best friend.
她是我最好的朋友。
They are my parents.
他们是我的父母。
⚠️ 常见错误 Common Mistakes
❌ I are a teacher. → I takes am: I am a teacher.❌ I 搭配 am：I am a teacher.（我是老师。）
❌ She are a doctor. → she takes is: She is a doctor.❌ she 搭配 is：She is a doctor.（她是医生。）
❌ We is students. → we takes are: We are students.❌ we 搭配 are：We are students.（我们是学生。）
F-02
be + 名词 / 形容词 / 地点
be 后面接什么💡 概念 Concept
After be comes: a noun for identity (a teacher), an adjective for a state or quality (hot, tired), or a place phrase (at home, in Shanghai). Chinese often leaves out the 'is' — English never does.be 后面接三类内容：名词表身份（老师）、形容词表状态或特征（热、累）、地点短语（在家、在上海）。中文常省略“是/在”，英语绝不可以省。
📐 规则 Rules
身份
be + 名词: My father is an engineer.
be + 名词：我爸爸是工程师。
状态特征
be + 形容词: The soup is hot. I am tired.
be + 形容词：汤很烫。我很累。
地点
be + 介词短语: We are at home.
be + 介词短语：我们在家。
✏️ 例句 Examples
My mother is a nurse.
我妈妈是护士。
The coffee is too hot to drink.
咖啡太烫了，没法喝。
They are in the classroom now.
他们现在在教室里。
⚠️ 常见错误 Common Mistakes
❌ I hungry. → English needs the verb: I am hungry.❌ 中文可以说“我饿”，英语必须加 be：I am hungry.（我饿了。）
❌ She is doctor. → Need an article: She is a doctor.❌ 单数可数名词前要有冠词：She is a doctor.（她是医生。）
❌ They happy. → They are happy.❌ 不能省略 are：They are happy.（他们很开心。）
F-03
There is / There are
存在句：某处有……💡 概念 Concept
To say something exists somewhere, English uses there is (singular or uncountable) and there are (plural), followed by the thing and then the place.表示“某处有某物”用 there is（单数或不可数）和 there are（复数），后面先说东西再说地点。注意：不要翻译成 there has。
📐 规则 Rules
单数
There is a book on the desk.
桌上有一本书。
复数
There are two cats in the garden.
花园里有两只猫。
不可数
There is some milk in the fridge.
冰箱里有一些牛奶。
不用 have
存在句用 there is/are，不用 there has / there have
存在句不用 there has / there have
✏️ 例句 Examples
There is a park near my home.
我家附近有一个公园。
There are many stars in the sky.
天空中有许多星星。
There is some water in the bottle.
瓶子里有一些水。
⚠️ 常见错误 Common Mistakes
❌ There has a book on the table. → There is a book on the table.❌ 存在句用 there is，不用 has：There is a book on the table.（桌上有一本书。）
❌ There are a bird in the tree. → Singular: There is a bird in the tree.❌ 一只鸟用 is：There is a bird in the tree.（树上有一只鸟。）
F-04
否定与疑问
存在句的否定与疑问💡 概念 Concept
Make there sentences negative with there isn't / there aren't (+ any), and ask questions with Is there ...? / Are there ...? Answer with Yes, there is / are, or No, there isn't / aren't.存在句的否定用 there isn't / there aren't（+ any）；疑问句把 is / are 提前：Is there...? / Are there...? 用 Yes, there is / are 或 No, there isn't / aren't 回答。
📐 规则 Rules
否定
There isn't any sugar. There aren't any students.
没有糖。没有学生。
疑问
Is there a bank near here? Are there any eggs?
这附近有银行吗？有鸡蛋吗？
简短回答
Yes, there is. / No, there isn't. Yes, there are. / No, there aren't.
是的，有。/ 不，没有。
✏️ 例句 Examples
There isn't any milk left.
没有牛奶剩下了。
Are there any good restaurants near here?
这附近有好餐馆吗？
No, there aren't, but there is a great one downtown.
没有，但市中心有一家很棒的。
⚠️ 常见错误 Common Mistakes
❌ There is no any water. → One negative only: There isn't any water (or: There is no water).❌ 不要双重否定：There isn't any water 或 There is no water。（没有水。）
❌ Are there some eggs? → Questions usually take any: Are there any eggs?❌ 疑问句一般用 any：Are there any eggs?（有鸡蛋吗？）