【多选题】某矿石由前 20 号元素中的 4 种组成,其化学式为 WYZX 。 X 、 Y 、 Z 、 W 分布在三个周期,原子序数依次增大, W 、 Y 为金属元素, X 原子的最外层电子数是次外层电子数的 3 倍, W 能与冷水剧烈反应, Y 、 Z 原子的最外层电子数之和与 X 、 W 原子的最外层电子数之和相等, Y 、 Z 位于同周期, Z 单质是一种良好的半导体。下列说法正确的是 ( )
【简答题】定语从句与状语从句 Directions: For each statement there are 4 choices marked A. B. C. and D. You are required to choose the correct answer. 1. He attended school in England for several years, after ____ he ret...
【简答题】From my perspective, I don't subscribe to this idea and I even regard this idea as an obstacle to children’s growth. 2. The supply manager considered the correcting typewriter an unneeded luxury. 3. A...
【简答题】—Ted’s flight from Amsterdam took more than 11 hours. He _____ be very tired after such a long trip. —Yes, especially after working all night before the flight. 2. _____ there is still a long way to g...