邻近既有线施工桥梁时,承台基坑边缘距离既有线外股钢轨5m以内,基坑开挖时必须申请对线路采取()措施
A.封锁
B.限速慢行
C.正常速度
D.提速
参考答案:B
The professor stressed the new medicine would _______ shorten the treatment period from the current days to a minimum of four days.
A.alternatively
B.effectively
C.actively
D.negatively
适用于高压钢管焊接的坡口形式是()。
A.V形
B.I形
C.U形
D.Y形