持信用卡人每日柜面取现笔数最多为()笔。
A.3
B.5
C.6
D.10
参考答案:A
I _____________ to the park yesterday. [ ]
A. walk
B. walked
C. walks
已知数列{an}是等差数列,且a1=2,a1+a2+a3=12
(Ⅰ)求数列{an}的通项公式
(Ⅱ)令bn=an+2n,求数列{bn}前n项和Sn.