弹钢琴手指要多少厘米

3.All flights _______ because of the snowstorm,many passengers could do nothing but take the train.A) had been canceled B) have been canceled C) were canceled D) having been canceled 为什么选择B?独立主格结构不是选D吗? 双曲线x^2/a^2-y^2/b^2=1的左右焦点F1F2,点P在其左支上,设P到左准线距离为d,d PF1 PF2成等比数列,求双曲线离心率的取值范围. I spend 50 yuan on this chair.改为同义句. so they left Britain,to which they were never to return为什么never后面要加to do?为什么还有be动词呢?不应该是in which they never returned吗?这是高中必修二里的 Two firemen were overcome by smoke.They were trying to put out the fire.请问这里,消防员为什么是被烟给战胜了呢? 在正三角形中ABC中,点D、E分别是AB、AC的中点,则以B、C为焦点,且过D、E的双曲线的离心率 人生第一次转折点什么意思 LOST FOUND Ⅱ怎么样 当方程m(x^2+y^2-4x+2y+5)=(3x+4y+33)^2所表示的点的轨迹为双曲线时,实数m的取值范围? Add one more body to the body toll.May God rest this poor bastard's soul. Because of tomorrow is Valentine's day,so I want to be more strong,both body and soul.这句话有没有语病 soul meets body这首歌的中文意思是什么? 请多多支持我,英文翻译Please give me -------.这个教室长十米,6米宽the classroom is----- 英语翻译与其在虚拟的世界里游走,不如把一分一秒都消耗于现实生活中.这里的消耗不是消极的,不代表着虚度,而是做自己喜欢的且有意义的,例如：看书,听音乐,运动等等.赶快摆脱对电脑游 已知双曲线C的方程为y^2/a^2-x^2/b^2=1(a>0,b>0),离心率e=√5/2,顶点到渐近线的距离为2√5/5.（1）求双曲线C的方程；（2）P是双曲线C上的一点,A,B两点在双曲线C的两条渐近线上,且分别位于第一,第二 双曲线x平方/a平方 -y平方/b平方=1（a>0,b>0)的右顶点为A,x轴上有一点Q（2a,0）,若C上存在一点P,使向量AP*向量PQ=0 ,求此双曲线离心率的取值范围 求与定点A(5,0)及定直线l:x=16/5的距离的比是5:4的轨迹方程 已知椭圆c1和双曲线c2：16分之x平方－9分之y平方＝1有公共焦点,点p（6,√7）在椭圆c1上,求椭圆c1的方程. 1.已知双曲线x^2/4-y^2/9=1,F1,F2是其两个焦点,点M在双曲线上,若∠F1MF2=90°,求△F1MF2的面积我想用F1F2来算.但是后面算不来了.注意!是双曲线啊!不是椭圆!2.双曲线中心在原点,焦点在坐标轴上,e为√2 谁有chance的 she drop MP3格式发给我吧 Little( )for money though he could have been very richA.did he care B.cared he C.had he cared D.he cared mp3格式chance she drop 音乐传给我 790127727 帮帮 I have little money,so I can buy____ books A.little B.little C.few D.a few 谁有chance的 she drop MP3格式? chance的 she drop mp3格式发给我吧 You have done very__ for me .是填few还是little 为什么? 急求she drop的mp3格式!邮箱：wm2009wang@163.com to drop the 一道英语宾语从句的题目,说明理由.1.Does your teacher know ______?A.when he has come B.why he didn't comeC.if he comes tomorrow D.whom he is looking Drop the verse 猴子最讨厌什么线求大神帮助 猴子最讨厌什么线?拜托各位大神