◎ 本句型中it be后的部分通常是表示時(shí)間的詞語,when引導(dǎo)的是時(shí)間狀語從句,意為“時(shí)間是……,當(dāng)……時(shí)候”。
It was about ten o'clock when the fire broke out. 火災(zāi)發(fā)生時(shí)大約在10點(diǎn)鐘。
比較
It was midnight when I got home. 我到家時(shí)已是午夜。
It was at midnight that I got home. 我是在午夜才到的家。(強(qiáng)調(diào)句型)