—I hear your grandpa has an old cup in your home. —Yes. It ______ drinking tea long ago and my grandpa _____ drink tea with it when he was young. A. was used for; was used to
Can’t you stay ______ the weekend? And then we can visit some other places of interest here. A. over B. on C. at D. in
为检验亚硫酸钠溶液中是否混有硫酸钠，应使用的试剂是( ) A.BaCl2溶液 B.Ba(NO3)2溶液C.BaCl2溶
定义=ad-bc,则符合=0的点P(x,y)的轨迹方程为______________.
在氯氧化法处理含CN的废水的过程中，液氯在碱性条件下可将氰化物氧化成氰酸盐(其毒性仅为氰化物的千分之一)，氰酸盐进一步被氧化为无毒物质。某
More and more foreign students come to China to learn______ Chinese． A．a B．an C．the D．不填
图是1940～1947年中国报刊上“民主”出现频率统计图。其中1946年“民主”出现频率较高的最主要原因是 A．抗战胜利后，民众渴望和平民主 B．国共重庆
Keep on trying. Never _________. I am sure you will succeed sooner or later. A. lose hearts B. lose your heart C. lose heart D. lose your hearts
