助动词是协助主要动词构成谓语动词词组的词, 助动词是语法功能词,自身没有词义,不可单独使用,助动词用法有一下几种: 1)have +过去分词,构成完成时态,例如: He has left for London. 他已去了伦敦。 By the end of last month, they had finished half of their work. 上月末为止,他们已经完成工作的一半。 2)have + been +现在分词,构成完成进行时,例如: I have been studying English for ten years. 我一直在学英语,已达十年之久。 3)have+been +过去分词,构成完成式被动语态,例如: English has been taught in China for many years. 中国教英语已经多年。 助动词be的用法 1) be +现在分词,构成进行时态,例如: They are having a meeting. 他们正在开会。 English is becoming more and more important. 英语现在越来越重要。 2) be + 过去分词,构成被动语态,例如: The window was broken by Tom.. 窗户是汤姆打碎的。 English is taught throughout the world. 世界各地都教英语。 |