题目

实验中需用2.0mol/L的Na2CO3溶液950ml，配制时应选用的容量瓶的规格和称取的质量分别为A．950ml；201.4g            B．1000ml; 212g         C．100ml; 21.2g               D．500ml; 100.7g  答案：B解析: The students are ________ the beautiful music. [     ]A. listening toB. listeningC. hearing