在混凝土中掺入硅灰可以减少混凝土的离析、泌水现象。()
参考答案:对
— Are these seats available?
— Sorry, sir. The seats _____.
A.have reserved
B.are reserved
C.reserved
D.are reserving
船舶在浅水区航行,如水深沿船宽分布不均匀,会出现船首向()现象.
A.浅水一侧偏转
B.左侧偏转
C.深水一侧偏转
D.右侧偏转