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举一反三
【单选题】下列溶液一定呈中性的是 [ ]
A.
c(H+)=c(OH-)=10-6mol/L溶液
B.
pH=7的溶液
C.
使石蕊试液呈紫色的溶液
D.
酸与碱恰好完全反应生成正盐的溶液
【单选题】Cell Phone Lets Your Secret Out Your cell phone holds secrets about you. Besides the names and (51) that you’ve programmed into it, traces of your DNA linger (逗留) on the device, according to a new s...
A.
explanation
B.
discovery
C.
book
D.
list
【单选题】TEXT B We all have offensive breath at one time or another. In most cases offensive breath emanates from bacteria in the mouth, although there are other, more surprising causes. Until a few years ago,...
A.
thrive on
B.
account for
C.
originate from
D.
descend from