非谓语动词的一般式表示的动作与谓语动词表示的动作同时发生或在其后发生,非谓语动词的完成式表示的动作发生在谓语动词表
示的动作之前。
1.动词不定式
例1:A lot of young people are learning to drive cars. (同时发生)
例2:All of us expected to discover... [阅读全文]
一.段落的特性
1.单一:Pollution has become a serious problem about which we worry. Wherever we turn we find pollution: polluted air, polluted water, polluted food and polluted environment. As we know, this is threatening the very survival of the... [阅读全文]