在混凝土中加掺和料或引气剂可改善混凝土的黏聚性和保水性。
参考答案:对
When asked about their opinions about the schoolmaster, many teachers would prefer to see him step
aside ________ younger men.[ ]
A. in terms of
B. in need of
C. in favour of
D. in praise of
生理有效辐射