问题补充：
You can’t imagine what great trouble they have the problem.
A. to solve; being talked about
B. solving; discussing
C. to solve; to talk about
D. solving; being discussed
答案：
A. to solve; being talked about
B. solving; discussing
C. to solve; to talk about
(答案→)D. solving; being discussed
解析：本题考查非谓语动词。第一个空考查定语从句。 定语从句为they have the problem .部分，其中考查词组：have trouble (in )doing sth. trouble作为先行词提前。第二个空考查词组：have sth. done 的结构，意为“使...被”
