如图的装置中,下列说法不正确的是
A.发生变化前的浓氨水是无色液体
B.发生变化前酚酞溶液是无色液体
C.放置一段时间后,浓氨水先变红
D.放置一段时间后,酚酞溶液先变红
答案:C
To have a dinner at a restaurant on the Eve of the Spring Festival, you need to reserve the restaurant
months before it, ____? [ ]
A. mustn't you
B. didn't you
C. don't you
D. needn't you
基础立柱倾斜的允许误差为()。
A、1%;
B、2%;
C、3%;
D、1.5%。