（8分）用符号“>”“<”或“=”连接下列各项关系。（1）第一电离能N______O； （2）电负性：N______C；（3）键的极性：H－C______
下列词语中加点的字，每对的读音各不相同的一组是（ ） A．刊载／载体 行伍／行若无事 殷红／殷切期望 B．哄动／哄传 上乘
如图1-2-6,梯形ABCD中,点E、F分别在AB、CD上,EF∥AD,=.试探究EF、AD、BC之间的关系,并证明.图1-2-6
_______ wonderful advice you have just________ me! A. How; told B. What a; given C. How a; sent D. What; given
—When will Mother come back? —She _____ to be here by eight o’clock tonight. is supposing B. supposed C. was supposed D. is supposed
细胞核内行使遗传功能的结构是（ ） A.核膜 B.核孔 C.染色质 D.核仁
I don’t mind picking up your things from the store. _________ the walk will do me good. A. Sooner or later B. Still C. In time D
酒后驾车是引发交通事故的重要原因。交警对驾驶员进行呼气酒精检测的原理是：橙色的K2Cr2O7酸性水溶液遇乙醇迅速生成蓝绿色Cr3+。下列对乙醇的描述
