位于我国地势第二级阶梯上的旅游景点包括： A.黄果树瀑布、布达拉宫、敦煌莫高窟 B.云冈石窟、陕西半坡遗址、庐山 C.承德避暑山庄、张家界、神农
如果x2＋mx－n＝(x+3)(x－2)，则m＋n的值为______．
I would be grateful if you would ____ receipt of this letter. A.admit B. acknowledge C. accept
1923年梁启超在《五十年中国进化概论》中写道：“革命成功将近十年，所希望的件件都落空，渐渐有点废然思返，觉得社会文化是整套的，要拿旧心理
一辆卡车初速度v0为10m/s，超车过程的加速度a为2m/s2，求：1.卡车在3s末的速度v 2.卡车在6s内的位移x6 3.卡车在第6s内的位移x6/
Technology is making life easier for some dairy farmers. They use robotic systems to milk their cows. Cows are trained to follow a series of paths that lead to milking stations. Only one cow at a ti
He has been studying German for five years and speaks _______ German. A. fluent B. fluently C. smooth D. smoothly
(x+1)2≥x2
2x+1≥0
x=-
.
,+∞).