采用滴定法测定水中氨氮(非离子氨)时,应以()为吸收液。
A.硫酸溶液
B.硼酸溶液
C.氢氧化钠溶液
参考答案:B
With more people ____ the traffic rules, our city is becoming better organized.
A.respect
B.being respected
C.respected
D.respecting
铁的吸收部位主要在
A.胃B.十二指肠和空肠上端C.空肠下端和回肠D.回肠E.回盲部