某些金属离子及其化合物能够为生物所吸收,并通过食物链逐渐()而达到相当的程度。
A.减少
B.增大
C.富集
D.吸收
参考答案:C
— I think 20 dollars for it is OK.
— No, I'd gladly pay ______ for it.?[ ]
A. twice as much
B. twice of what?
C. the price twice
D. as much twice
IR()
A.气相色谱法
B.高效液相色谱法
C.十八烷基硅烷键合硅胶
D.红外分光光度法
E.差示扫描量热法