问题 选择题

The man was determined to deal with the problem on his own and turned down ______ of help.    [ ]

A. invitations    

B. offers    

C. applications  

D. comments

答案
B
选择题
函数f(x)=log2x在区间[a,2a]上的最大值是最小值的2倍,则a等于(  )
A.
1
2
B.
2
2
C.
2
D.2