【简答题】课内阅读 1961年,一位名叫S.M.斯季绍夫的前苏联科学家发现,如果二氧化硅(即非常纯的沙子)处于超高压的状态,那么它的原子相距很近,从而变得极为致密。一立方英寸被压扁的沙子比一立方英寸普通的沙子要重得多。这种被压扁的沙子因此被称为“斯石英”。 斯石英并不十分稳定,原子之间靠得太近以至于它们又出现相互排斥的趋势,最后又变为普通沙子。然而,由于原子之间结合得极为致密,所以这种反弹变化进行得非常缓慢...
【多选题】关于数据字典正确的描述是( )。
B.
实现数据字典三种常见的方法有全人工过程、全自动过程、混合过程
【单选题】SARS突发性公共卫生事件属于下列突发公共卫生事件的哪一类( )
【简答题】渐缩喷管在出口断面上最大只能达到 速流动,而缩放喷管在出口断面上则可以达到 速流动,此时其喉部气流一定是 速流动。
【多选题】关于数据字典正确的描述是( )
B.
实现数据字典三种常用方法有:全人工过程,全自动过程,混合过程
【单选题】I've been going home for lunch ever since I started school. I never liked eating in the cafeteria(自助食堂) although in tile seventh grade, because all the other boys were doing it and thought it was cool...
A.
he never ate in the cafeteria
B.
he ate in the cafeteria sometimes but not often
C.
he always went back for lunch
D.
he often ate in the cafeteria
【简答题】Conversation 2 1. What are the two speakers talking about? A. Famous people. B. American society. C. History exam. D. Civil war. 2. Which of the following is true? A. The two speakers are discussing t...