is加動詞過去分詞是什麼時態

is的用法

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