They all think the problem needn’t . It isn’t worth at all.A. discussing; discussingB. to

问题补充：

They all think the problem needn’t . It isn’t worth at all.

A. discussing; discussing

B. to be discussed; discussing

C. be discussed; discussing

D. to be discussed; being discussed

答案：

A. discussing; discussing

B. to be discussed; discussing

(答案→)C. be discussed; discussing

D. to be discussed; being discussed

解析：句意：他们都认为这个问题不需要讨论。它根本不值得讨论。结合语境可知前文中need为实意动词，表示需要的含义。这个问题是被讨论的对象，故用被动语态。下文为固定句式be worth doing指的做某事，故选C。