国标规定：硅酸盐水泥的初凝时间（），终凝（）。 A.不大于45mi_爱下问搜题

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问题单项选择题

国标规定：硅酸盐水泥的初凝时间（），终凝（）。

A.不大于45min，不小于390min

B.不大于45min，不小于600min

C.不小于45min，不大于600min

D.不小于45min，不大于390min

答案

参考答案：D

选择题

I was wondering ________ that you took up smoking. [ ]

A. it when was

B. when it was

C. it was when

D. was it when

判断题

教导、示范是家庭德育的基本方式，只要与儿童生活和身心发展水平相适应，无须与家庭生活相联系，也可以做到行之有效。