②单数概念主语用is, 复数概念主语用are
I am a teacher. You are my friend. He is a boy. She is a girl. It is an apple.
Tom is his brother. Tom and Jerry are his brothers.
主语是一句话的中心，，其位置一 般放在句首，主语主要由名词、代 词，动名词或起名词作用的短语或 从句来充当。 eg: Li Lei is a Chinese boy .(Li lei 是名词，作主语) eg: He is from England .(He是 代词，作主语)
Be 动词: am, is, are ① 我( I) 用am, 你(you)用are, is 连着他(he)、 她(she)、它(it)
④主系表结构句子要变为一般疑问句， be 前提，句末问号莫丢弃 一般疑问句：用 Yes或No来回答的句子
This is my sister. 变为一般疑问句： Is this your sister?
Yes, she is./ No, she is not. (is not 缩写为isn’t)
These are my parents.变为一般疑问句：
主语+系动词+表语 （主系表结构）
系动词分为： 1.状态系动词 (be动词: am, is, are) 2.感官系动词 3.变化系动词 4.保持系动词
主语+be (am, is, are)+表语——————含义：
Be和表语一起说明主语的状态或性质等
I am a teacher. The students are in the classroom. Our classroom is big.
表语： 表语和Be动词一起用来修饰主语，说明主 语的身份、性质、品性、特征和状态的，表 语位于系动词之后。表语一般是名词，形容 词，介词短语,代词等。
I am a teacher.
It is an apple. It is a pen. It’s an orange.
It is yellow. It is black. It is orange. My friend is in China. This book is mine.
用Be动词（am, is, are) 填空：
am a student. I____
is Jack. My name____
is my sister. She____
are my friend. You____
is an apple. It____
is yellow. It____
is a nice girl. She_____
1.琳达是一个聪明的女孩。 Linda is a clever girl. 2.琳达很聪明。 Linda very clever. (×) Linda is very clever. 3.现在她8岁了。 Now she eight years old. (×) Now she is eight years old. 4.她在大理。 She in Dali. (×) She is in Dali.
is a boy. He____ are my parents. They_____ are friends. Tom and Peter______ are very happy. My parents____ are in Kunming. We_____
那些花儿非常漂亮。 Those flowers areБайду номын сангаасvery beautiful. 莉莉的钢笔在书桌上。
They are my parents.
③变否定，也容易， be 后not加上去
I am a teacher.变为否定句： I am not a teacher. You are my friend.变为否定句： You are not my friend. Tom is his brother. 变为否定句： Tom is not his brother. They are my parents. 变为否定句： They are not my parents.
Lily’s pen is on the desk. 杰克来自美国。 Jack is from America.
张明明在丽江。 Zhang Mingming is in Lijiang.
Thank you!
See you next class!
Are these your parents?
Yes, they are./ No, they are not( are not 缩写为aren’t)
Linda’s telephone number is 605-4279.
（改为一般疑问句）：
Is Linda’s telephone number 605-4279? Yes, it is./ No, it is not.(is not 缩写为 isn’t)
主系表结构
（主语+系动词+表语）
英语的五种基本句子结构
1.主语+谓语 如：A bird can fly. 2.主语+系动词+表语 如：He is a boy. 3.主语+谓语+宾语 如：I love you. 4.主语+谓语+双宾语（直接宾语+间接宾语） 如：She gives me an orange. 5.主语+谓语+宾语+宾语补足语 如：You make me happy.