什麼時態中when表示就在此時
進行時態或一般將來時態
1、was/were doing +when 意思為“就在這時,正在這時”。
如:
  I was walking in the street when someone called me from behind. 我正在街上走,就在這時有人從後面叫我。
  They were discussing the problem when the teacher came in. 他們正在討論問題,就在這時老師進來了。
& about to 意思為 “正要/正準備做某事,就在這時……”。
如:
  She was about to go out when an unexpected visitor came. 她正準備出去,這時來了一位不速之客。
  We were about to set out when it began to rain. 我們正要動身,就在這時開始下雨了。
&+表示狀態的介詞短語+when意思為 “正在做某事,就在這時……”。
如:
  They were at work in the office that afternoon when a big fire broke out.那天下午他們正在辦公室工作,就在這時一場大火發生了。
  We were on duty in the classroom when a boy rushed in. 我們正在教室裡值日,就在這時一名男孩衝了進來。
  Li Ping was on his way home when two boys stopped him.李平正往家走,突然兩個男孩攔住了他。
1、將when翻譯成當……時候,此時主句與從句時臺一樣.2.將when翻譯成……就在這時.有三個常用句型 doing ……正在做什麼,就在這時