你认为排尿有什么意义呢？__________________。

阅读理解

     Different countries and different people have different manners. We must find out their customs so

that they will not think us ill-mannered(没有礼貌的). Here are examples of the things that a person

with good education does or does not do. If you visit a Chinese family, you should knock at the door

first. When the door opens, you will not move before the host says "Come in, please." After you come

into the room, you would not sit down until the host asks you to take a seat. When a cup of tea is put

on a table before you or sent to your hand, you will say "thank you" and receive it with two hands. not

one hand or they will think you arc ill-mannered. Before entering a house in Japan, it is a good manner

to take off your shoes. In European countries, even though shoes sometimes become very dirty, this is

not done. In a Malay house, a visitor never finishes the food on the table. He leaves a little to show that

he has had enough. In England, a visitor always finishes the drink or the food to show he has enjoyed it.

That will make the host pleasant.

根据短文内容，回答下列问题

1. Does the writer think it is necessary to know different customs in different countries?

2. When can you enter the room if you visit a friend in China?

3. What should you say when a cup of tea is sent to your hand?

4. In which country do you have to take off your shoes when you enter the host's house?

5. Why does a visitor always finish the food at dinner in his friend's home in England?

（）是引起可燃物本身自燃的原因。

A.发酵生热

B.氧化生热

C.分解生热

D.吸附生热

一般情况下，施工总承包管理不与分包方和供货方直接签订施工合同，这些合同都由( )直接签订。

A．设计方

B．项目总承包方

C．业主方

D．工程监理方

2006年6月某电厂扩大生产车间，结构采用钢结构工程，横向20m跨、钢柱与钢梁之间采用高强螺栓连接、钢彩板屋面，墙体砌筑围护，2005年8月开工，2006年7月竣工验收合格。

高层建筑的钢柱通常以( )层为一节，吊装一般采用一点正吊。

A．1～3

B．4～5

C．6～7

D．2～4

关于食管蠕动的叙述，错误的是

A．第一蠕动波又称为原发蠕动
B．第二蠕动波又称为继发蠕动
C．第三收缩波是非推进性蠕动
D．第一蠕动波由吞咽动作诱发
E．第二蠕动波起始于剑突水平