从属连词before的用法归纳.doc

从属连词 before 的用法归纳 江西省金溪县第一中学 杨赛文before 一词在高中课本中出现频率极高， 是历届英语高考的考点，同时又是学生学习的难点本文就 before 用作从属连词的用法归纳如下： 1. 如果主句动作与从句动作按时间先后依次发生，before 意思为“在......之前” 例如：They had got everything ready before I arrived.在我到达之前，他们就把一切都准备好了Make sure the light is turned off before you leave the classroom.离开教室前确保灯关掉2. 如果强调从句动作发生迟缓，before 意思为“过了多久后才......” 例如：They walked about 30 miles to the west before they saw a village.他们西行了大约 30 英里才看见一个村庄The big fire lasted four hours before the firemen brought it under control.大火持续了四个小时，消防队员才把它控制住。

3. 如果强调主句动作发生迅速，before 意思为“还没来得及......就; 尚未......就......” 例如:She left the company before I could have a word with her.我还没来得及和她打声招呼, 她就已经离开了公司Before I could figure out what had happened, he forced me into the car.我尚未知道发生了什么，他就强行把我推进了汽车4. before 表示“以免，免得”类似于 in order not to, 强调动作的必要性，以避免或防止从句动作的发生例如：I’ll write it down before I forget it.我得记下来以免忘了We’d better finish the work in time before the boss scolds us.我们最好按时完成这项工作，免得挨老板的骂5. before 表示“宁愿......决不......; 与其....毋宁......”,类似于 rather than, 常与 will 或 would 连用。

例如：He will die before he apologize to the general manager.他宁死也不向总经理道歉I’ll give up the plan before I turn to him for help.我宁可放弃计划也不会向他求助6. before 表示“只有......才能” 例如：We must study hard before our dream can come true.只有通过努力学习，我们的梦想才能实现You must persevere before you can succeed.只有持之以恒，你才能成功7. before 表示“一......就; 刚刚......就”, 与 hardly , scarcely 连用例如：He had hardly gone to bed before the door bell rang.他刚刚睡下，门铃就响了She had scarcely got off the train before her daughter ran towards her.她刚下火车，女儿就跑了过来8. before 表示“不知不觉就......; 还没有弄清楚就......” 。

例如：Time passed quickly and three weeks went by before they knew it.时间过得很快，不知不觉他们已经度过了三个星期He was so absorbed in his work that four hours had passed before he knew it.他如此专注于工作，不知不觉四个小时就过去了9. before 表示“趁......还没有......”, 类似于 when 引导的状语从句， 从句，从句肯定形式表示否定意义例如：Work hard before you are old.趁年轻时努力学习Let’s blow before they catch us.趁他们还没有抓到我们时赶快溜吧10. before 用于某些习语中，表示“先......再” 例如：Look before you leap.三思而后行Be a pupil before you become a teacher.先当学生，后当老师11. 用于“It + be/take +时间段+before” 句型在这一句型中，主句和从句的时态有两种情况：（1）主句用一般将来时，则从句用一般现在时。

若主句是肯定形式时，意思为“要过多长时间才......”; 若主句是否定形式时, 意思为 “用不了多久就......”例如：It will be two weeks before everything returns to normal.两周之后一切才能恢复正常It won’t be long before we meet again.用不了多久我们就会再见面的2）若主句用过去时，从句也用过去时若主句是肯定形式时，意思为“多长时间之后才......”; 若主句是否定形式时, 意思为 “没过多久就......” 例如：It was some time before I realized the truth.过了很长一段时间我才了解到真相It wasn’t long before she became a brave soldier.没过多久她就成了一名勇敢的战士。