I hope we only have half an hour homework, so we can have more time our hobbies.A. of, o

I hope we only have half an hour homework, so we can have more time our hobbies.
A. of, of
B. of, for
C. for, for
D. for, of

A. of, of(答案→)B. of, forC. for, forD. for, of解析：句意：我希望我们只有半小时的作业，那样我们就有更多的时间给我们的业余爱好。of的，for给；半小时的作业，名词所有格；留出更多的时间给爱好，故选B.

这个问题我还想问问老师呢