Question

The boy found himself in a bad situation when________in the river.

A.swimming B.swims C.to swim D.swam

Answer

A

【解析】

句意：那男孩在河里游泳时发现自己处境很糟。

考查动词形式。when引导的时间状语从句，若从句的主语与主句的主语相同时，从句的主语省略，并将谓语动词变成分词。句中主语与游泳之间为主动关系，用现在分词。例如，When you do the work, you should be careful.=When doing the work, you should be careful.故选A。