数列前10项的和为（）．
A.选项A
B.选项B
C.选项C
D.选项D
参考答案：B
解析：
因为
，所以b1+b2+b3+…+
故选B．
Faced with such a hard financial problem, Jack tried to stand on his own two feet rather than turn________ his parents.
《外科心法要诀》说 “痈疽原是 生”。
前10项的和为（）．
，所以b1+b2+b3+…+
故选B．
前10项的和为（）．，所以b1+b2+b3+…+故选B．