下列物质中属于弱酸的物质是()。
A.HCL
B.HNO3
C.H2CO3
D.HAC
参考答案:C, D
We received £1550 in cash and promises of another £650, making £2200 .
A.in all
B.after all
C.by the way
D.on the way
“支撑员”技术等级“应会”考试应有()成员参加评定。