They sometimes go on working the light of the moon.A. onB. underC. byD. for

问题补充：

They sometimes go on working the light of the moon.

A. on

B. under

C. by

D. for

答案：

A. on

B. under

(答案→)C. by

D. for

解析：固定搭配,by the moon light ,by the light of the moon在月光下.