The man caught ___our defense work was tired and sentenced to 10 years in *
问题描述：
The man caught ___our defense work was tired and sentenced to 10 years in *
A to have spied on Bspying on C to be spies on D being spied on
答
catch sb.doing sth.
抓住某人做某事
这里用的是catch 过去分词,表示被动,做man的后置定语,所以用了spying