化合物丙由如下反应得到丙的结构简式不可能是( ) A.CH3CH2CHBrCH2Br B.CH3CH（CH2Br）2C.CH3CHBrCHBrCH3
下列各项按出现时间先后排列的正确顺序是：（ ）①票号 ②交子 ③柜坊和飞钱 ④五铢钱A、④③②① B、③④②① C、④②
分解代谢应指 ①吸收营养物质 ②合成自身物质 ③分解自身物质 ④储存能量 ⑤释放能量 ⑥排
（几何证明选讲选做题）如图，圆 O 的割线 PBA 过 圆心 O，弦 CD 交 PA 于点F，且△COF∽△PDF，PB = OA = 2，则PF = 。
以下有关物理学概念或物理学史说法正确的有（ ） A．牛顿发现的万有引力定律，卡文迪许用实验方法测出万有引力恒量的数值，从而使万有引力定律
The film “Red Cliff “ ______ great success when it made its first appearance on the screen. A. appreciated B. enjoyedC. won D. seized
Then comes the July, and with it are examinations; but these are soon finished and with them ends the school year. Boys and girls have nearly two months holiday before them as they leave school by
阅读下面的文字，根据要求作文。（60分）有一家创业者顾问公司做了一个很有趣的实验：从一群创业者中召集了十个志愿者，首先，让这十个人穿过一
