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【单选题】
下列各组溶液，有缓冲作用的是（ ）A.
0.2 mol/L KCl
B.
0.02 mol/L NH3· H2O
C.
0.2 mol/L NaH2PO4和0.2 mol/L Na2HPO4
D.
0.01 mol/L HAc和0.2 mol/L HCl
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皮皮学刷刷变学霸
举一反三
【单选题】根据下列文章,请回答 1～20 题。{Page Read the following text. Choose the best word(s) for each numbered blank and mark A,B ,C or D on ANSWER SHEET1. Generally speaking, a British is widely regarded as a quiet, shy...
A.
relaxed
B.
frustrated
C.
amused
D.
exhausted
【简答题】Read unit 4 text A The Open Window carefully, and complete the summary of it with the following words. entertained, to his horror, runs off, nervous, hunted, killed, distract, socialize, at short not...
【单选题】Speaker A: Mr. Lee, everyone is here except Kate.She is ill in bed Speaker B: _______________________________
A.
What bad news!
B.
I’m sorry to hear that
C.
I t doesn’t matter
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