Though it was late he went on with his work.A. andB. butC. /D. so

问题补充：

Though it was late, he went on with his work.

A. and

B. but

C. /

D. so

答案：

A. and

B. but

(答案→)C. /

D. so

解析：句意：虽然很晚了，然是他继续他的工作。A和 B但是 D因此；though不能和but连用，所以这里什么也不填。故选C.