A:成正比例
B:成反比例
C:不成比例
— Does your son ________an hour ________ his homework after school?
— No, shorter than that now, about half an hour.
读下图回答题此时亚洲东部盛行( )
在数列{an}中,“an=2an﹣1,n=2,3,4,…”是“{an}是公比为2的等比数列”的( )