为保证混凝土的工程性质，混凝土所用的水泥细度越细越好。
参考答案：错
捡拾到他人遗失物，可以据为已有，不违法。[ ]
"Will you be able to finish the job this week?" " ___ ."
A．I can't say it
B．I don't know that
C．I'm not sure this
D．I don't expect so
