When he came back three hours later they were still on the sofa in conversation.A. sitt

问题补充：

When he came back three hours later, they were still on the sofa, in conversation.

A. sitting ; absorbing

B. sitting ; to absorb

C. seated ; absorbed

D. seated ; to be absorbed

答案：

A. sitting ; absorbing

B. sitting ; to absorb

(答案→)C. seated ; absorbed

D. seated ; to be absorbed

解析：考查分词用法。Seated adj就坐；be absorbed in…沉浸于…；第一空可以用sitting表示状态也可以用seated。第二空用absorbed修饰they的状态。句意:当他3个小时候回来的时候，他们仍然做在沙发上，沉浸于对话中。故C正确。