_____ will greatly decide their future, most senior 3 students think, is their grades．

 The buses, most of _________ were already full, were surrounded by an angry crowd.

(2013·陕西，18)I have heard a lot of good things about you ________ I came back from abroad.

Since ______ to the world, the dance “GangnamStyle” has caused a release of a certain feeling.

 He made another wonderful discovery, ____ of great importance to science.