单项填空。
Let's ______ to a restaurant to have lunch. [ ]
A. go
B. to go
C. going
D. goes
答案:A
1909年丹麦科学家Sorense用公式pH=-lgc(H+)引入pH,1999年科学家Henk Van Lubeck提出酸度概念,定义AG=lg[c(H+)/c(OH-)],下列叙述错误的是[ ]
A.常温时,中性溶液的pH=7,AG=0
B.酸性溶液的AG>0,AG越大,溶液的pH越小
C.碱性溶液的AG>0,AG越大,溶液的pH越大
D.常温时,碱性溶液中AG=14-2pH
—Is this your ________ visit to my hometown,Zunyi?
—No.I’ve been here for many times.
A.one B.the first C.first