起升高度大于（）的起重机在臂架头部应安装风速仪；当风速大于工作极限风速时，应能发出停止作业的警报。
A.30
B.40
C.50
D.60
参考答案：C
For women life sometimes seems ____ it is for men.
A．twice as hard as
B．as twice hard as
C．as hard twice as
D．as hard as twice
任何单位不得以虚假的经济业务事项或者（）进行会计核算。
A．原始凭证
B．记账凭证
C．资料
D．会计资料
