当离心泵输送液体的重度增大时，其扬程（）
A、升高
B、不变
C、下降
参考答案：B
Only when I left my parents for Italy _____ how much I loved them. [ ]
A. I realized
B. I had realized
C. had I realized
D. did I realize
测定水样的碱度时，可测得酚酞碱度，但再加入甲基橙指示剂时无反应，可判断该水样中只含有HCO3－碱性离子。（）
