已知椭圆的中心在原点，以坐标轴为对称轴，且经过两个点，，求椭圆的标准方程．
The engineer __________my father works is about 50 years old. A.to whom B.on whom C.with which D.with whom
下列现象中，属于增大压强的是（ ） ①载重量大的汽车装有许多车轮 ②压路机上碾子的质量很大 ③短道速滑运动员的冰鞋上装有冰
She often a train to school, sometimes she goes to school bus. A. takes, takes B. takes, by C. by, takes D. by, by
在图幅大小相同的一组地图上( ) A．比例尺越大，图幅所示范围越大 B．比例尺越大，图幅所示范围越小 C．比例尺越大，图幅所示内容越粗略 D．
--Well, my sons take great interest in most of the food on the menu. --Thanks. _______________?--Yes, fried fish, beef, chips and cola, please.A．Can I do for youB．At your serviceC．What to fol
在△ABC中,三个内角∠A、∠B、∠C对应的边分别为a、b、c,且∠A、∠B、∠C成等差数列,a、b、c成等比数列,求证:△ABC为等边三角形.
--What are you going to do this afternoon? -- I am going to the cinema with some friends. The film ____ quite early, so we ____ to the bookstore after that. A. finished; are going
