ore forests being destroyed , huge quantities of goodearth each year

Mr. Hu, can you tell us how to learn swimming well—Sure. But remember we can learn nothing well _______ hard work.

______ without friends ______ the most difficultchallenge for Chuck while living on the island

Where ____ Wang Jun and Mr. Li from —They are from Shanghai.

Why does the lake smell terrible — Because a large amount of water_______.