问题补充：
When and where to build the new schoolyet.
A. have not been decided
B. are not decided
C. has not been decided
D. has not decided
答案：
A. have not been decided
B. are not decided
(答案→)C. has not been decided
D. has not decided
解析：when and where to build the new school指的是“一件事”,故谓语动词用单数形式,且decide一词用作及物动词,所以应用被动语态。
