道岔外锁闭装置

明朝的结婚年龄? 我将来会跟谁结婚? 已知等比数列{an}的公比为q,前n项和为Sn,求[Sn*Sn+2-（Sn+1）^2]/[an*an+2]已知数列{an}为等比数列，Sn为前n项之和.若S3S4-S4^2=-16，a2a4=32，求S4的值. 好的追分What's your favourite colour?Do you like yellow,orange o___ red?If you do,you must be a person full of hope and h___ feelings about life.If you love green,you are strong-minded.You wish to do everything w____and want other people to see y 初三英语200不要求全部做,看我最后要求!Nasreddin was a poor man,so he tried to grow __1__ he could in his own garden,so that he would not have to buy so many in the market.　　One evening he heard a noise in his garden and looked out 【急+好的追】初三英语首字母求助!A bark (狗吠) is a sound a dog makes to communicate something to people or other animals. A bark can be a f 97 way to say “hi.” Sometimes dogs bark to tell their o 98 that they see people they do n 1.American film ____ on TV last Sunday evening.A.has shown B.was shown 2.When and where to go for a holiday ____ yet.A.are not decided b.have not been decided c.is not being decided d.has not been decided据汉语提示写单词3.Do you know the ____ 在一个顶点的周围有m个正三角形的角,n个正方形的角,求m和n的值 一般人是左脑灵活还是右脑灵活咧? 印章中按照印文的凹凸,可分为两种引文形式分别为 印章中按照印文的凹凸,可以分为两种印文形式有哪两种? 印章中按照印文的凹凸,可以分为哪两种? 印章中按照印文的凹凸,可以分为两种印文形式,是哪两种? 一条关于高二等比数列的前n项和的数学题目已知Sn=1+2×3+3×3²+4×3³+……+n×（3的n-1次方）,求Sn.我知道是用错位相减法,但是还是不知道咋做,求详细过程~ 印章可以分为哪两种印文形式 要完善体制机制是什么意思 “制度” “机制” “体制”三者的区别及联系.“相应地” 意思是什么 圆柱的侧面积怎么求 角的大小是由什么决定的? 求圆柱的侧面积和体积#includemain(){\x09double r,h;\x09scanf("%f",&r);\x09scanf("%f",&h);\x09printf("s=%.2f\n",2*3.1415926*r*h);printf("v=%.2f\n",h*3.1415926*r*r);} I don't know if it () tomorrowIf it ()tomorrow ,we will just stay at home.A.will rain;rainsB.rains;rainsC.will rain;will rainD.rains;will rainI'm sorry.I didn't mean to bother you.-()but i do want to be alone for a moment.A.all rightB.that's all righ 用食指指他人用英语怎么说 探究人类生男和生女的几率 男人和女人,从生物学角度分析,哪个更花心? 孙子兵法的注解,要全文做出系统的解释,不要只有其中几篇的,要全篇的,最好是像语文书那样的, 孙子兵法中的风林火山, 分析化学中的“最低浓度的1：G怎么理解,可以结合实例说明吗谢谢. 【物理题】请写出从图像中获得的两条信息： 如图所示,已知角l:角2:角3=l:3:2,三角形AOB的面积是12平方厘米,求阴影部分的面积? 哈师大生物科学详情 哈师大三批生物科学多少分?求助状~~~~