Question

—Can you describe _____ it happened?
　　—Yes, I was riding on my bike _____ a car knocked me down from behind.

A．when; as

B．how; as

C．how; when

D．how; while

Answer 1

C

解析试题分析：句意：你能描述一下它是怎么发生的吗？好的，我正在骑自行车时，突然一辆车从背后把我撞倒了。when突然 。故选C
考点：be doing…when句型
点评：除上述句型外，还有be about to do sth…when正将要做…突然，注意理解when的意思，而while表两个动词同时发生。as表“一边…一边”“随着”之意。