Whose idea is it?

这是谁的主意？

《新英汉大辞典》

Someone, somewhere might have a slightly better idea of some of this, but my academic friend, whose job it is to try to understand the illness, is exasperated by the difficulty of finding out the basics.

BBC: A scanner to detect terrorists

Now it seems that African leaders have decided that unity is an idea whose time has come.

BBC: Q&A: African Union

Is it a good or bad idea to give this supplement to kids whose sleep schedules may be thrown off by a time change or some other factor?

CNN: Should your teen take melatonin for help with sleep?