锤造全冠一般为
A．刃状边缘B．凿状边缘C．凹形边缘D．肩台形边缘E．斜面形边缘
参考答案：A
Some students are seriously ill and they can't class for several days. [ ]
A. give
B. attend
C. make
D. assume
根据《中国移动900/1800MHzTDMA数字蜂窝移动通信无线网工程验收规范》，如铁塔高度超过（）m，馈线应在铁塔中部增加一处接地。
A.50
B.55
C.60
D.65
