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为了帮助大家有效备考英语四六级考试，读书人编辑整理了一些资料供大家参考：
十八、be + forced/compelled/obliged + to + V (不得不……)
例句：Since the examination is around the corner, I am compelled to give up doing sports.
既然考试迫在眉睫，我不得不放弃做运动。
十九、It is conceivable that + 句子 (可想而知的)
It is obvious that + 句子 (明显的)
It is apparent that + 句子 (显然的)
例句：It is conceivable that knowledge plays an important role in our life.
可想而知，知识在我们的一生中扮演一个重要的角色。
二十、That is the reason why ~~~ (那就是……的原因)
例句：Summer is sultry. That is the reason why I don’t like it.
夏天很燠热。那就是我不喜欢它的原因。
二十一、For the past+ 时间，S + 现在完成式……(过去……年来，……一直……)
例句：For the past two years, I have been busy preparing for the examination.
过去两年来，我一直忙着准备考试。
二十二、Since + S + 过去式，S + 现在完成式。
例句：Since he went to senior high school, he has worked very hard.
自从他上高中，他一直很用功。
二十三、It pays to + V ~~~ (……是值得的。)
例句：It pays to help others.
帮助别人是值得的。
二十四、be based on (以……为基础)
例句：The progress of thee society is based on harmony.
