桥梁上部结构的施工中,混凝土的振动采用插入式振动器进行,振动器的移动间距不超过其作用半径的( )。
A.1倍
B.1.5倍
C.2.0倍
D.2.5倍
参考答案:B
The island, ____ to the mainland by a bridge, is easy to go to. [ ]
A. joining
B. to join
C. joined
D. having joined
无性孢子(asexual spore)