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双曲线的第二定义是什么? 双曲线第二定义证明 1、Is that her schoolbag?——No,that isn't.改错 2、Is this your watch ——Yes,it‘s.改错 双曲线第二定义问题 问PF=ey-a（p为双曲线上任意一点）怎么推出来的? E-schoolbags.Is your schoolbag too heavy The e-schoolbag will help you .It is said that e-scho Is your schoolbag too heavy?The e-schoolbag will help you.It is said that e-schoolbags are going to be brought into (16) ______in Chinese middle schools soon.Heavy schoolbags have been a serious (17) _____ for a long time,but the e-schoolbags will (1 人类的起源及怎么样发展的 Do you know that girl ____ long hair?什么情况下有长头发用have,如果前面有动词了,那么人+什么介词+头发? 求比喻句和拟人句以及排比局句子多些,字少些． and what is that in your( )( is it a pen? Is that your pen?作否定回答 最好画图说明 ___is your pen.A This B That C It D Its 选哪个? 挂靠证书什么意思 that is your pen. 双曲线的基本定义 双曲线的概念虚轴是什么,它和实轴有什么关系? it is said that he has not came here .疑问句怎么变?无 关于双曲线的第二定义,在双曲线的左半轴上取一个点P,连接P和右焦点F2则PF2和P到右准线的距离之比是否为E? Who is that ocer here?It is 反意疑问句 nobody is here ______? 车和刃组字念什么音 人类 起源于非洲还是亚洲?我在一本书上看到说是起源一我们中国!我不知道是真的还是假的 人类的祖先真的是起源于非洲吗?我看一些报道,现代人类的祖先,包括欧洲,亚洲,美洲等都是从非洲来的不知道这有什么科学依据? 人类来源于非洲,也就是说,地球所有的人都是非洲人后代,我们都应该去非洲祭拜祖先 作文 写一篇为长辈做一件事 以：说说我家的老人,为题写一篇600字的作文.要用一件事来说 _________computer games too much is bad for your eyesA.To play B.Play C.Playingwhy 作文 老人印象 写一件事或者以报告的形式来写老人 450字左右写一件事或者以报告的形式来写老人 好的话再多加分!~急!~!~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 不要网上拉来的 —How much is your computer?—It' s _____________dollars.A.four thousands and eight hundred B.f选项有4个：A.four thousands and eight hundredB.four thousands and eight hundredsC.four thousand eight hundredD.four thousands eight hundred 一件被大人称赞的事的作文该怎么写?做一件被大人称赞的事,以这个为主题,写一篇作文. How much is your coat?怎么回答