下列变化肯定属化学变化的是( ) A.爆炸 B.酒精挥发 C.雾散天晴 D.燃烧

题型:选择题

问题:

下列变化肯定属化学变化的是(  )

A.爆炸

B.酒精挥发

C.雾散天晴

D.燃烧

考点:物理变化和化学变化的特征和判别
题型:选择题

假定英语课上老师要求同桌之间交换修改作文,请你修改你同旧式写的以下作文。文中共有10处语言错误,每句中最多有两处。错误涉及一个单词的增加、删除或修改。

增加:在缺词处加一个漏字符号(∧),并在其下面写出该加的词。

删除:把多余的词作斜线(\)划掉。

修改:在错的词下划一横线,并在该词下面写出修改后的词。

注意:1. 每处错误及其修改均仅限一词;

2. 只允许修改10处,多者(从第11处起)不计分。

Ladies and gentleman,

May I have your attention, please?         

All flights this morning have put off, because our air is covered with thick fog. As there has no wind, the weatherman is unable to tell that the fog will clear up. We cannot do anything but waiting. Please keep in order and take good care of your baggage. Passengers, please don’t leave for the waiting room. As soon as the weather turns favorable, and we shall announce flights. For passengers stayed at the airport, lunch is free. It will    be served in the dining hall in the second floor from eleven o’clock to one o’clock. By the way, there is no plane to arrive within a hour.

题型:选择题
我们已经知道
3
×
3
=
3×3
=
32
=3
,显然把上面的步骤反过来写3=
32
=
3×3
=
3
×
3
也成立,运用这种方法可将一些根式化简,如:
(1)
18
=______;(2)3
3
-
75
=______;(3)
2
7
=______.(4)
7-
7
7
=______.
题型:选择题

保护性耕作技术的主要特征是:不使用()耕翻土壤,()覆盖地面。

题型:选择题

使用杀毒软件可以检查和清除所有的病毒。( )

题型:选择题

下列关于西亚和东南亚的叙述,错误的是[ ]

A.地理位置都很重要

B.都是世界上重要的石油产区

C.两区的纬度位置都较低,降水都较少

D.西亚人口稀疏,东南亚人口稠密

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