第1个回答 2009-03-14
While the alien was buying a souvenir,the girl called the police.
When the girl called the polie,the alien was buying a souvenir.
简单点说,while带有一点对比,然而,同时,持续
而when 就是当。。。时,瞬间不持续
What were you doing when the UFO arrived这句话意思是当UFO出现的时候你正在做什么。
例如:When he was drinking,his wife came back.
当他在喝酒的时候,他妻子回来了
如果对was drink提问,就该是他妻子回来的时候他在做什么
What was he doing when his wife came back.