下列关于功率的说法中正确的是[ ]
A.做功越多,功率就一定越大
B.功率越大,做功的时间就一定越短
C.功率越大,做功越快
D.功率的大小表示做功的多少
答案:C
---- What do you think of Tom’s playing football.
------ I think he plays football ______ , if not better than, Jack.
A.very well
B.so well
C.as well as
D.wonderfully
利用分子离子峰可以测定分子量。( )