塔式起重机工作时，风速应低于几级。（）
A．4
B．5
C．6
D．7
参考答案：C
It is ________ room. They like it very much. [ ]
A. Li Lei's and Li Ming's
B. Li Lei's and Li Ming
C. Li Lei and Li Ming's
D. Li Lei and Li Ming
经皮肾镜取石或碎石术为（）
A.输尿管结石
B.膀胱结石
C. * * 结石
D.肾结石
E.纯尿酸结石
