1. He must be from Africa, _________ can be seen from his skin.答案：B. as 解释：as确实可以引导方式状语，比如I did the work as my father taught me.但是，这里是定语从句，只不过先行词不是一个名词或者代词，而是整个句子。在非限制性定语从句中，which和as可以引导定语从句修饰整个句子，注意that、where、when、why等都不行。举列子：They did rather badly in the maths exam,which was not what I had expected.句子中，“They did rather badly in the maths exam” 是我所没意料到的。还有就是 as we all know 结构：As we all know, china is a developping country.这里we all know 的内容就是“china is a developping country”这整一句话。补充一下，as引导方式状语时，从句式完整的句子，而引导定语从句时，则从句缺少成分，比如As we all know，缺少的就是know 的宾语，而宾语其实就是主句“china is a developping country”2. I was about to go shopping _________ it began to rain. 答案：C. when 解释：固定句型be about to do ……when……表示正要做某事时，突然另一件发生，这题的意思就是：当我正要去购物的时候突然下雨了。 when在此句做并列连词，类似于and then“就在这时”，引导的是并列句。它并不是从属连词以引导时间状语从句。when此种用法如果用在过去时的并列句中时，前句有三个特点，即：可能使用过去进行时，或过去完成时，或was about to do sth结构，而后句则使用一般过去时。而as是没有这种用法的（as做从属连词引导时间状语从句时，更多强调主从句动作同时进行）。如：I was sleeping when the telephone rang. 我正在睡觉，就在这时电话响了。I had waited for 3 hours when he came at last. 我已经等了3个小时了，就在这时他终于来了。I was about to leave when the door opened. 我正要离开，就在这时门开了。
最爱的mango
