（）不是组成铸钢摇轴支座的部件。
A.上下摆
B.锚栓
C.底板
D.摇轴
参考答案：B
有一列数A1，A2，A3，A4，A5，…，An，其中A1=5×2+1，A2=5×3+2，A3=5×4+3，A4=5×5+4，A5=5×6+5，…，当An=2009时，n的值等于 [ ]
A.334
B.401
C.2009
D.2010
In America．a friend's inviting you to a restaurant doesn't mean that he or she will pay for the meal you are told in advance．
A．unless
B．if
C．although
D．until
