题干
My study in junior high school is coming to an end. It's time ____us_______.
A：for, graduate
B：to, to graduate
C：for, to graduate
D：to, graduating.
答案(点此获取答案解析）
C
FeS与b mol FeO投入到V L、c mol·L-1的硝酸溶液中充分反应，产生NO气体，所得澄清溶液成分可看作是Fe(NO3)3、H2SO4的混合液，则反应中未被还原的硝酸可能为（ ）
)mol
