on rescuing her sick son, the poor mother has been working 16 hours a day.
A. To bend
B. Being bent
C. Having bent
D. Bent
网友回答
A. To bend
B. Being bent
C. Having bent
(答案→)D. Bent
解析：句意：这位可怜的母亲决意要治好她生病的儿子，现在已经工作16个小时了。Bent在这里是形容词： 执意要的；有强烈意向的；决心的，决意的，与on，upon搭配。故选D。
考点: 考查非谓语动词的用法。