many times the problems were settled at last.A. Having discussedB. Being discussedC. To

问题补充：

many times, the problems were settled at last.

A. Having discussed

B. Being discussed

C. To be discussed

D. Discussed

答案：

A. Having discussed

B. Being discussed

C. To be discussed

(答案→)D. Discussed

解析：

这里考查过去分词做原因状语的用法，因为句子的主语是the problems和discuss是被动的关系。所以用过去分词做状语。句意是因为被讨论了很多次，这些问题最终被解决了。