下载APP
举一反三
【多选题】碳化对混凝土的影响有（）。
A.
使混凝土产生收缩，在其表面产生微裂纹
B.
可减少水泥石的孔隙
C.
使混凝土的碱度增强
D.
对钢筋的保护能力降低
E.
使混凝土抗压强度有所提高
【单选题】Passage Three In recent years there has been an increasing number of large oil spills. These spills, some of which have occurred directly at the site of extraction and others during tran...
A.
immediately
B.
after quite a long time
C.
few years later
D.
after several months