N-（1-萘基）-乙二胺光度法测定水中亚硝酸盐氮的测定上限为（）mg/L。
A．0.10
B．0.20
C．0.30
D．0.40
参考答案：B
May I __________ you? Yes, I want to buy a bike.[ ]
A. watch
B. go
C. help
稠密：稀疏
A．宽敞：明亮
B．词语：词汇
C．伟大：平凡
D．酷热：炎热
