糖类和蛋白质是生物体内重要的有机化合物，下列关于糖类和蛋白质的有关说法，不正确的是（ ） A．糖类又称碳水化合物，因此，糖类的分子式都可
22. ---Mike! Don't tell me you are the guy I am waiting for? It can't be true! ---Yes, I am the guy. ---What a bummer, _________. A.You set me up. B. I don't know C.What if D.You ar
现有四种晶体，其离子排列方式如图所示，其中化学式不属AB型的是 A B C D
MOSCOW, Sept. 4 (Xinhuanet)--- At least 335 people including 155 children, were killed in the three---day hostage crisis (人质危机) in a southern Russian school, Russia’s Deputy Pro
What a beautiful pen! Where _________it? A. do you buy B. did you buy C. were you buying D. have you bought
世界年平均气温分布图上，南半球等温线比较平直，原因是南半球( ) A．地势低平 B．平原面积广阔 C．海洋广阔 D．受
测量苹果的密度有许多方法：（1）方法一：如图所示，用天平测得苹果的质量为 g，若苹果的体积为200cm3，则苹果的密度为 g/ cm
聚合物 (结构简式)可被人体吸收，常作为外科缝合手术的材料，该物质由下列哪种物质聚合而成( ) A．CH3CH(OH)COOH B．HCOOCH2OH C．HOCH2CH2COOH D．HOCH(CH3)COOCH(C
中，
，则
= ▲ ．