冒泡排序算法的时间复杂度是什么？

阅读理解

       Hundreds of years ago, life was much harder than it is today. There was no modern medicine. 

       Life today has brought new problems. One of the biggest is pollution. Water pollution has made our

rivers and lakes dirty. It kills fish and pollutes our drinking water. Noise pollution makes us talk louder and become angry more easily. Air pollution is the most serious kind of pollution: It's bad to all living things in

the world.

       Cars, planes and factories all pollute our air every day. Sometimes the polluted air is so thick that it is

like a quilt over a city. This kind of quilt is called smog(烟雾).

       Many countries are making rules to fight pollution. Factories must now clean their water before it is

poured into rivers; they mustn't blow dirty smoke into the air.

       We need to do many other things. We can put waste things in the dustbin instead of throwing it on the ground. We can go to work by bus or with our friends in the same car. If there are fewer people driving,

there will be less pollution. Rules are not enough. Every person must help to fight pollution.

1. Hundreds of years ago, life was much harder than it is today because____.     

A. there were not any modern machines     

B. there was no pollution     

C. both A and B     

D. there were not many people   

2. What is the biggest problem in today's life?     

A. Water pollution.    

B. Air pollution.     

C. Noise.            

D. Pollution.  

3. The most serious kind of pollution is___       .   

A. noise pollution    

B. air pollution     

C. water pollution    

D. A, and C

4. Factories must clean their water____           

A. before they are poured into rivers     

B. when they are poured into rivers     

C. after it is poured into rivers     

D. before it is poured into rivers   

5. From the passage we know that________    

A. a few years ago, there was no smog at all     

B. today people don't have to talk to each other in a loud voice     

C. We can drink water from the polluted rivers and lakes     

D. people are making rules in order to fight pollution

已经结婚登记的夫妻，在执行下列( )行为后，婚姻关系才能解除。

A．(A) 撤销登记

B．(B) 宣布婚姻无效

C．(C) 法院调解

D．(D) 离婚

组合钢钢模板使用时间长、磨损小，在管理和使用中通常采用（）的方法。

A.购买

B.租赁

C.借用

D.期货

荧光光谱是物质分子（）

A.接受了火焰的热能而发射出的光谱

B.接受了电能而发射出的光谱

C.接受了光源的激发光光能而发射出的光谱

D.接受了电的热能而发射出的光谱

E.接受了光源的光能而发射出的光谱

长途光缆机线设备的维护分界，是以长途光缆进入传输站（或中继站）的第一个连接器为界，连接器以外由线路维护分队维护，连接器属（）维护。

A.线路维护分队

B.主管部门

C.传输站

D.抢修中心