新概念英语三册 Lesson20 Pioneer pilots 第（3）套免费课件

I anxiously packed my things up while waiting to pick up my children.
我一边等着去接孩子，一边焦急地收拾东西。
Would you be good enough to pick up the tickets for me today?
你今天能去帮我拿票吗？ 
I picked up English when I worked in a training class as part-time job.
我在一个培训班做兼职时无意中学会了英语。
when从句的谓语动词可以在主句谓语动作之前、之后或同时发生；while和as从句的谓语动作必须是和主句谓语动作同时发生。 
1．从句动作在主句动作前发生，只用 when。 
When he had finished his homework，he took a short rest．（finished先发生）当他完成作业后，他休息了一会儿。 
2．从句动作和主句动作同时发生，且从句动作为延续性动词时，when，while，as都可使用。 
①When ／While ／As we were dancing，a stranger came in．（dance为延续性动词）当我们跳舞时，一位陌生人走了进来。 
3．在将来时从句中，常用when，且从句须用一般时代替将来时。
When the manager comes here for a visit next week，Ill talk with him about this．下周，经理来这参观时，我会和他谈谈此事。