主谓一致中,两个疑问句并列,谓语动词用单数还是复数?

题目

主谓一致中,两个疑问句并列,谓语动词用单数还是复数?
eg,when they will come and where we should go ˍ（is/are）still unkown.

答案

这里指的是两件事,所以要用复数are
如果指的是同一件事,如When and where to hold the party ________(has/have）not been decided yet ,就用has