你能说一说have和has的用法吗（说的详细一点,也别太复杂了能让3年级的人听懂）多举举例子 说说什么情况下用have

当主语是第三人称单数（he , she ,it ) 或单数名词( Daming , my father等）时,用has
例：She has many books. Amy has a cute dog.
当主语是第一人称（I, we ）,第二人称（you) ,第三人称复数（they) 或复数名词（ the boys, my parents, my friends等）时,用have
例：I have a computer. They have some apples. The boys have a football.

have 用于第一人称、第二人称和名词复数 例句：I have a book. You have a book.
Pencilcases(笔袋) have pencils. They have books.
has 用于第三人称单数、名词单数 例句：He/she has a book.
It has a tail(尾巴). The bag has many books.

1.have 用于第一人称，比如说 I 例句：I have a book.
has 用于第三人称 比如说 He She it 例句：He/she/it is happy