一般现在时和一般过去时句型结构的异与同：

　　(1) 一般现在时表示某人某物现在的状态，性质等．eg:

　　I  am  a  teacher now.

　　She(He) is  a  singer.

　　We / They / You are happy.

　　(2) 一般过去时表示过去时间内某人某物存在的状态，性质等．eg:

　　I  was  a  teacher last   year.

　　She / He was  a  singer.

　　We / You  / They  were  happy.

　　例句：

　　It was a duckling. Now it is a duck.

　　It was rainy yesterday. It is windy today.

　　The sofa was under the shelf. Now it is under the window.

　　练一练：

　　We___ (be) at home last night.

　　A. are

　　B. is

　　C.was

　　D. were

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