绝热材料的主要特征包括（）。A、气孔率高 B、体积密度小 C、导热系数小 D、重烧收缩小

根据短文内容填空。

      One day, the mother rat and her babies were having a good time in the open air when a cat came to catch

them for her dinner. The mother rat noticed the cat coming near. The mother rat and her babies all tried to run

away at once. They hurried to their home. It was under the tree. But the baby rats were afraid of the cat. They

couldn't run very fast. The cat came closer and closer. She would come at them. " What shall I do? " thought

the mother rat. Just at that moment the mother rat stopped running, turned around and shouted at the cat,

" Bowwow. Bowwow! " Just like an angry dog. The cat was so surprised and afraid that she ran away. The

mother rat turned to her babies, " Now you see how important it is to learn a second language! "

1. What were the mother rat and her babies doing?

    They were having a ___________ ___________ in the open air.

2. What was coming close to the rats?

    The ___________ was coming close to the rats.

3. Where was the rats' home?

    It was the ___________ the ___________.

4. Why couldn't baby rats run very fast?

    Because they were ___________ ___________ the cat.

5. At last, what did the mother rat do to get rid of the cat?

    The mother rat stopped ___________, turned around and ___________ at the cat just

like an angry ___________.

解下列方程：

（1）（x﹣2）²﹣81=0；

（2）27x³+1000=0。

声频在16～20kHz之间称为（）。

A.不可听声

B.可听声

C.超声

D.次声

ICD-10关于抑郁发作的诊断标准对于症状持续时间的要求是（）

A.至少2周

B.至少3周

C.至少4周

D.至少5周

E.至少1周

考生文件夹下有一个数据库文件“samp2.mdb”，其中存在已经设计好的一个表对象“tBook，请按以下要求完成设计。

创建一个查询，查找并显示单价大于等于15且小于等于20的图书，并显示“书名”、“单价”、“作者名”和“出版社名称”4个字段的内容，将查询命名为“qT2”。