∴t＝∴t＝
﹣t， ，
＝，
②当OQ＝PQ时，在Rt△BOD中，cos∠AOD＝如图2，过点Q作QM⊥OD于M， ∴OM＝OP＝（
﹣t），
在Rt△OMQ中，OM＝OQcos∠AOD＝t ∴（∴t＝
﹣t）＝t， ，
③当PO＝PQ时，如图3， 过点P作PH⊥OB于H， ∴OH＝OQ＝t，
在Rt△POH中，OH＝OP?cos∠AOD＝（∴t＝（∴t＝
，
秒或
秒或
秒．
﹣t），
﹣t），
∴△OPQ为等腰三角形时，t的值为
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并列句and 和，并且， work hard, and you can pass the exam. but 但是he is rich but he is not happy. Or 否则，要不然，或者（在否定句中表和）Hurry up, or you’ll be late. so 因此，所以Kate was ill so she didn’t go to school. For 因为 I have to stay up late, for I have a lot of work to do. 状语从句当状语从句的引导词为If, when, before, after, until, as soon as等，主句和从句有下列情况：英语句子中如果一看到 Thought----but----; because----so---这种结构就是错误倒装句so+助动词\\BE动词情态动词另一主语，表示后者与前者一致。so+上句主语助动词\\B动词情态动词，真的，确实如此。Tom watched TV last night, so did Ann.Tom didn’t watch TV last night. Neither did Ann. ---You’ve left the light on. --So I have. I’ll go and turn it off. 宾语从句从句用陈述句语序。主句与从句的关系。．主现从不限；．主过从过；．真金不怕火炼。The earth moves around the sun.
赠送—初中英语总复习知识点归纳第22页（共24页）
③常见的宾语从句。She says that ---- I hope / think / feel / wonder---- I wonder if he will join us in the discussion tonight. Could you tell / show me--- Could you please tell me where the teacher’s office is? Do you know---- Do you know where Mr. Li lives? Please tell me --- She asked me ---I don’t know ---- I don’t know whether Tom will go or not.定语从句that和hich在指物的情况下一般都可以互换, 但在下列情况下, 一般用tha而不用whic。(1) 先行词为all, everything, nothing, something, anything, little, much 等不定代词时。I am sure she has something (that) you can borrow.(2)先行词被all, every, no, some, any, little, muc等修饰时。I’ve read all the books that are not mine.(3)先行词被序数词或最高级修饰时。This is the first book (that) he has read.(4)先行词被the only, the very, the same, the last修饰时。This is the very book that belongs to him.一般用that而不用who(1) 先行词是who或who引导的主句。Who is the girl (that) drove the car? Who (that) broke the window will be punished.(2) 主句以There be引导时。 There are 200 people (that) didn’tthat和hich在指物的情况下一般都可以互换, 但在下列情况下, 一般用which而不用tha。(1)关系代词在限制性定语从句中紧跟介词作宾语（介词提前）。Those are many trees under (which) they can have a rest.(2) 在非限制性定语从句中。 Football , (which) is a very popular game, is played all over the world.后跟ing 的词有Finish doing Before 2008 Beijing we will finish building the Olympic Park. enjoy doing 喜欢做某事 I enjoy reading English loudly.mind doing 介意（反对）做某事 would you mind opening the window?practice doing sth. 练习做某事 we should practice speaking English as often as possible. be busy doing sth. 忙于做某事be worth doing sth. 值得做某事feel like doing sth =want to do sth. 想要做某事spend --- (in) doing sth 花费时间做某事stop / prevent / keep ----from doing 阻止某人做某事have trouble \\problem / a hard time doing sth. 做某事很困难Have fun doing sth. =have a good time doing sth. 做某事很快乐go on doing sth 接着做原来做着的事go shopping / swimming/ skating /surfing---do some running / washing/ cooking ---介词(for, with, without, about ---)后跟动词原形why don't you why not you'd better (not) would you please (not) make\\ let \\ have\\ [注意: 在被动语态中 t o 要加上后跟ing 和TO 的区别第23页（共24页）
developing country 发展中国家developed country 发达国家stop to do sth.停下手中的事而去做另外的事（事情有两件）Stop doing sth. 停止正在做的事情（事情只有一件）Remember to do sth.记住要去做某事（事情没有做）Remember doing sth. 记得曾经做过某事（事情已经做）Forget to do sth. 忘记去做某事（事情没做）Forget doing sth. 忘记曾经做过的事情（事情已经做）Try to do sth.努力去做某事Try doing sth.试着去做某事Go on to do sth. 做完一件事，接着改做另外一件事Go on doing sth. 继续不停地做某事See / hear sb doing / do
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