The old man abroad for twenty years is on the way back to his motherland.A. to workB. wo

问题补充：

The old man, abroad for twenty years, is on the way back to his motherland.

A. to work

B. working

C. to have worked

D. having worked

答案：

A. to work

B. working

C. to have worked

(答案→)D. having worked

解析：本题考非谓语动词。句中两个逗号中间的内容应是时间状语，故全句解释为：在国外工作了二十年后，这位老人（已动身）正在归国途中。不定式作状语，多表目的和结果，不合句意，排除A、C，分词作状语可表时间、方式、伴随。此处是已完成的主动的动作，不是正在进行当中的主动动作，所以排除B，选D，现在分词完成式表主动和完成（到谓语发生时，非谓语的动作已完成）。