A.CO2
B.CO
C.NO2
D.SO2
答案:B
— How do you like Guilin?
— It is the most beautiful place ______ I have ever been to.
A.where
B.which
C.that
D.what
在保持流动性及水泥用量不变的条件下使用减水剂,可使混凝土( )
A.减少拌合水量
B.降低水灰比
C.强度提高
D.增大坍落度
E.增大水灰比