英语里when表示一.就意思when 的词组,比如hardly...when.had...when(这个不确定)

1.be doing sth.whene.g.We were having a meeting when someone broke in.2.be about to do sth.whene.g.We were about to set off on our way whenit suddenly began to rain.3.be on the point of doing whene.g....