英语四级语法知识在中,单独考察的题几乎没有,但是语法知识点却贯穿整张试卷,下面是为大家整理的知识,希望可以为大家带来帮助,一起来学习一下吧。
19.8 比较while, when, as 1)as, when 引导短暂性动作的动词。 Just as / Just when / When I stopped my car, a man came up to me.
2)当从句的动作发生于主句动作之前,只能用when 引导这个从句,不可用as 或 while。 When you have finished your work, you may have a rest.
3)从句表示"随时间推移"连词能用as,不用when 或while。 As the day went on, the weather got worse. 日子一天天过去,天气越变越坏。