He used to spend a lot of time computer games.

_____ of the water _____ polluted. We must try to protect our environment.

Daniel is my friend. I like sharing my _________ with him when I am happy.

Bob did everything than the other three students. Our teacher chose him to be our monitor.

Qinghai-Tibet Railway(青藏铁路) was completed last year. It is the __________ railway that connects Tibet with the other parts of China.