be动词

主语+be+adj （be不翻译）
形容词前一般加be动词：She is beautiful. He is honest. thay are tall.
主语+be+副词，介词（be= 在）
 I am here. He is at the station. your mother in the room.
主语+be+n(be=是)
I am a boy. She is a nurse. they are teachers.