水箱壁混凝土浇筑下料要均匀，做好由水箱壁上的两个对称点同时、同方向下料，以防模板变形。
参考答案：对
Mary three of her classmates invited to the party.
A．as well; has been
B．and; have
C．as well as；was
D．as good as; were
工程塑料ABS是一种三元共聚物，其成分为（）。
A.聚苯乙烯
B.丁二烯
C.丙烯晴
D.苯乙烯
