题目内容：

The doctor says that the problem with her husband's eyes（ ） by many reasons
A.cause
B.causes
C.is caused
D.are caused
快

优质解答

is caused(导致)
整句话的意思是“医生说她丈夫的眼睛的问题是由很多原因导致的”
此处应用被动语态,从句的主语是the problem,谓语动词用单数