— Did you see the boys yesterday afternoon?
— Yes. I saw them the fence when I passed.
A. climb
B. climbed
C. to climb
D. climbing
网友回答
A. climb
B. climbed
C. to climb
(答案→)D. climbing
解析：考查分词用法。See sb doing sth看见某人正在做某事；根据when I passed可知是在过去的一个时间点上发生的事情，那么应该是指正在进行的事情。句意：当我经过的时候，我看到他们正在爬篱笆。