1、二、句型剖析1.be to do sth.【典型例句】 The books you borrowed are to be returned before July 5.你所借的图书应当于7月5 日前归还。The train is to arrive in Beijing at 10:25 am.这趟火车将于上午十点二十五到达北京。(如果不定式用完成式，则表示“本来打算”。)As early as his second film,Chaplin had developed his own manner of acting,the one that was to become world-famo
2、us.早在他拍第二部电影的时候，卓别林就形成了自己的表演风格，后来闻名于世的就是那种风格。If it were to rain tomorrow,we would stay at home.如果明天下雨的话，我们就得待在家里。【要点归纳】 be to do sth.表示四层意义：应当/必须做，常用在通知和说明书里;按计划或安排将要做的事情;注定，表示将来不可避免要发生的事;用于虚拟语气【相关链接】 be to和be going to 辨析：be to 表示客观安排或受人指示而做某事。be going to 表示主观的打算或计划也可表示将来迹象。例如：Make your enemy your f
3、riend.化敌为友。I am to play football tomorrow afternoon.(客观安排)Im going to play football tomorrow afternoon.(主观安排)2.be allowed to do sth.被允许做某事【典型例句】 No smoking is allowed.禁止吸烟。The government servants arent allowed to accept rewards.公务员不得接受酬谢。【相关链接】 allow vt.允许,承认allow doing sth.允许干某事allow sb.to do sth.允许某人做某事3.be impressed by给某人留下极深的印象【典型例句】 We were most impressed with/by your efficiency.你的工作效率很高，我们极为钦佩。【要点归纳】 此句型还可以用为be impressed with/at.【相关链接】 impress(sth.)on/upon sb.使某人铭记、印象深刻His words impressed themselves on my memory.他的话铭刻在我的记忆里。
