问题补充：
with his work in the Satellite Launch Site，he could not spare any time to stay with his parents though they are very old.
A. As occupying
B. Occupied
C. Having occupied
D. To occupy
答案：
A. As occupying
(答案→)B. Occupied
C. Having occupied
D. To occupy
解析：考查过去分词作状语。be occupied with 忙于做某事，句意：他忙于他的工作在卫星发射基地，他不能抽出时间和他的父母在一起，尽管他们年纪大了。故选B。
