---- less homework,the students would have more time to play

不定式放句首,一般是作目的状语. 因此C项不正确.
若要表达"将被给予更少的家庭作业,学生们将会有更多的时间玩."
还是用 Given ,只不过谓动的would 要改成will . 这是一个真实条件句.
Given less homework , the students will have more time to play and have fun.
=If the students are given less homework ,. .(主将从现原则)

而此题既考查过分作条件状语,又考查了虚拟语气(由would have 得知), 表示与现在事实相反的情况.
Given less homework , the students would have more time to play and have fun.
=If the students were given less homework ,. .(事实是: 学生的作业多,玩的时间少)
再问： 好像不定式也可以表将来，对吧。
再答： 不定式是可以表将来动作,但放在句首,一般是作目的状语.这显然与句意不合. 因为句中表达的是条件状语.