问题补充：
When to go for the on-salary holiday yet?
A. are not decided
B. have not been decided
C. is not being decided
D. has not been decided
答案：
A. are not decided
B. have not been decided
C. is not being decided
(答案→)D. has not been decided
解析：句意：什么时候去带薪休假还没有决定呢。主语是疑问词+不定式的时候，谓语是单数，而且和yet连用，应该是现在完成时，所以选D。
