is的用法：

　　第三人稱he(男) +is ; she(女)+is; it(不是人)+is;其他單數(shù)名詞+is

　　例句：

　　HeShe is a good student.

　　It is a white cat.

　　A dog is on that street.

　　is也可與主語(yǔ)縮寫,如:

　　He is = He's, My mother is = My mother's等。

　　但是This is不可縮寫。而is與not可縮寫成 isn't。如:

　　This isn't a book.

　　這不是一本書。