问题
选择题
Mr. Smith, ______ in the factory for thirty years, is on the way back to his village.
A．to work
B．working
C．to have worked
D．having worked
答案
答案：D
题目分析：考查非谓语动词。for+一段时间，常与完成时连用，根据“for thirty years”可知，史密斯先生已经在这家工厂工作了30年，having worked相当于who has worked。故选D。