【名词&注释】
亚硝酸钠(sodium nitrite)、化合价(valence)
[单选题]亚硝酸钠(NaNO2)是一种工业用盐,外观酷似食盐,人若误食,会引起中毒。亚硝酸钠中氮元素的化合价是( )
A. +1
B. +3
C. +4
D. +5
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学习资料:
[单选题]----Dad, do you like my picture?----_______________! It’s the nicest one I’ve ever seen!
A. What beautiful
B. How careful
C. How wonderful
D. What wonderful picture
[单选题]7.—Do you want________ the park?—Yes, I do.
A. go to
B. to go
C. to go to
D. going to
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