验证酶的高效性实验成功的关键是[ ]
A．试管是否干净
B．肝脏是否新鲜
C．卫生香(或火柴梗)是否点燃
D．是否有对比实验
答案：B
He gave up _______ two years ago. That’s to say, he is a non-smoker now.
A. smoke B. smoking C. to smoke
银行业从业人员对所在机构的纪律处分有异议时，可以直接向监管部门反映和申诉。()
