(一段时间)当我出差北京时,希望见到你。 ②When the clock struck twelve, all the lights went out. (一点时间)当钟敲响十二下时,灯全部熄灭了。 while引导的时间状语从句只能表示“一段时间”所以 while从句的谓语动词应是延续性动词(或状态动词)。例如: ①While I stayed(or was) in Shanghai, I saw her three times. 我在上海期间见到她三次。 如果从句的谓语动词是延续性的,可以用while也可以用when。例 如: ②While(When) we were having a meeting, a stranger came in. 我们在开会时,一个陌生人走了进来。 3.still, yet和already的用法比较 1)still表示某事仍在进行中,意为“仍然”,“还”。例如: ①I am still busy, I have not finished my work yet. 我仍然很忙,我没有干完这个活儿。 ②How to take some useful things out of the waste materials and use them again is still a big problem. 怎样从废料中提取有用的东西并加以重新利用 (责任编辑:admin) |