下列变化，能证明硫酸是强酸的事实是 [ ]
A.能使石蕊试液变红
B.能跟磷酸钙反应制磷酸
C.能跟氯化钠反应制氯化氢
D.能跟锌反应产生氢气
答案：B
— Our city looks more beautiful!
— Yes. Lots of trees and grass ______ since last year. [ ]
A. have been planted
B. are planted
C. will be planted
D. were planted
客人到店后，客房未准备好，怎么办？
