粗骨料是指凡粒径大于（）mm的颗粒。
A.4.70
B.4.75
C.4.80
D.4.85
参考答案：B
一物体体积为100cm3，浸一半在水中受到的浮力是______N，浸没在密度为0.8×103g/m3的煤油中受到的浮力是______N．
A high-level language is an artificial language with which we can write various (66)
A．Files
B．instructions
C．text
D．papers
