— Is this your book?
— ______. [ ]
A. Yes, this is
B. Yes, it is
C.Yes, she is
答案:B
供热管道的地沟沟底应做不小于( )的坡度。
A.0.001B.0.002C.0.003D.0.004
普通混凝土和易性最敏感的影响因素是( )。
A.集料品种 B.水泥浆C.集料品质 D.砂率