be動詞什麼時間是連繫動詞

系動詞be

作爲系動詞（也叫連繫動詞，link verb）的be，其基本含義爲“是”，基本用法結構爲“主語+be+表語”，也就是常說的主系表結構，其中的表語一般都由名詞、形容詞、數詞或表地點、時間等的短語來充當。 系動詞be有各種時態的變化，也會和情態動詞連用。

1、be的時態變化 系動詞be會有一般現在時、一般過去時、一般將來時、現在完成時、過去完成時等的時態變化。

如：

He is a student.

They were in the park yesterday.

It will be cloudy tomorrow.

He has been ill for six days.

It had been three hours before she left the hat shop.

2、be與情態動詞的連用 其用法爲：情態動詞+系動詞be原形。

如：

It must be Lucy's book. Her name is on the cover.

It can be very difficult for us to memorize too many words within such a short time.

She should be here on time tomorrow