I am lihua,come from China.该句中come为何不用现在分词形式

I am lihua,come from China.该句中come为何不用现在分词形式 i am lihua, a student from beijing.这句话有什么错 I am/come from 还是I was/came from? i am from 和 i come from 为什么i come from 没有助动词呀? I come from America.i come from America.I am from America,I am an American.有什么区别? i come from china i后面还加am吗 I am Leo come from China.I am Leo from China.哪个正确? you,he and I [are/is/come/am] from china i am come from xiangtan.a city of hunan I am just come back from you I am just come back from you dream 我不懂 where do you come from?a I come from school.b.I am from china.选哪个? who am where I come from?and what I am doing?有语法错误吗 I come from China和 I am from China意思一样吗 I am from chongqing和I come from Chongqing改一般疑问句 特殊疑问句 英语作文She sports we like,开头是Hello everyone .I am Lihua.today I come from china.可以说I am from china.为什么这里不加be动词am了? I am come back. Where are you from 我写的是：I come from germany I am from germany 请问有区别吗