1.表示的是两个人或者物的时候用are,如果表示的是一
个人或者物用is
The boy and girs are playing tennis.
The writer and teacher is fond of music.
2.一些特殊情况
Each boy and each girl has a dictionary.
Every boy and every girl has a dictionary.
Many a boy and many a girl has a dictionary.
把and连接的看成整体的用is,反之用are