He insisted that hesuffer from heart trouble but I didn’t think so.A. should sufferB. has

问题补充：

He insisted that hesuffer from heart trouble, but I didn’t think so.

A. should suffer

B. has suffered

C. suffers

D. was suffering

答案：

A. should suffer

B. has suffered

C. suffers

(答案→)D. was suffering

解析：考查时态。句意：他坚称他正患心脏病，但是我不这么认为。可知前文描述的是过去正在发生的事情，故用过去进行时态。选D。