题目内容
_________ advertisements are of great help, I don’t think we should entirely rely on them.
| A．Since | B．While | C．Because | D．As |
B
解析试题分析：考查连词：A. Since自从，既然 B. While 虽然，当.. 时候，然而Because因为 D. As因为，当…时候，句意：虽然广告很有用，但我认为不能完全依赖它们。选B。
考点：考查连词辨析。
点评：此题主要考查连词的辨析，选择连词主要是看前后句的关系，因果关系用表因果的连词，转折关系用转折连词，并列关系用并列连词，要求考生具有一定的句子分析能力和词义辨析能力。
He said it would be at least three more months ________ he could recover and return to school.
| A．when | B．before | C．since | D．after |
_____ these experiments were successfully completed would we think of
going into humans.
| A．If only | B．So that | C．Only if | D．Even if |
—I’m going to the post office.
— you’re there, can you buy me some stamps?
| A．Because | B．While | C．As | D．If |
This approach, ______ more expensive than the basic one, provides us with considerably more usage flexibility.
| A．as | B．since | C．while | D．if |
He had his camera ready____ he saw something that would make a good picture.
| A．even if | B．if only | C．in case | D．so that |
They were about to leave it began to rain.
| A．before | B．durning | C．while | D．when |
Mary and I have been close friends ______ we met each other 10 years ago.
| A．when | B．since | C．until | D．as |
He didn’t come to school yesterday _______ that he was ill.
| A．because | B．for | C．in | D．if |