搜题请搜索小程序“爱下问搜题”
问题 问答题 简答题

MgO作硫化剂的效果。

答案

参考答案：

在高温（100℃以上）具有硫化作用，并能吸收硫化过程中产生的HCl和Cl2，在低温下具有稳定剂作用，能防止焦烧，但硫化时间长，且硫化程度不高。

单项选择题

A child watching television experiences a procession of sights and sounds that flash from the screen just long enough for the eyes and ears to take them in. Unlike the pages of a book, which can be read as slowly or as quickly as the child wishes, television images appear with a relentless velocity that stunts rather than. enhances the child’s powers of imagination.
The view expressed above is based on an assumption. Of the following, which can best serve as that assumption

A．When allowed to choose a form of entertainment, children will prefer reading to watching television.

B．A child’s imagination cannot be properly stimulated unless the child has access both to television and to books.

C．A child’s imagination can develop more fully when the child is able to control the pace of its entertainment.

D．Children should be taught to read as soon as they are able to understand what they see on television.

E．(E) A child’s reaction to different forms of sensory stimuli cannot be predicted, since every child is different.
查看答案
单项选择题 案例分析题

图中①②③④4条折线表示四地正午太阳高度的季节变化情况，⑤曲线表示四地中的某地昼长随季节变化的情况。据此回答下列各题。

关于②③两地比较分析，正确的是（）

A.只考虑太阳辐射时，气温年较差：Ｔ③＞Ｔ②

B.植被、土壤类型相同

C.降水：Ｒ②＞Ｒ③

D.②地作物一年三熟，③地作物两年三熟
查看答案