A
Without proper planning，tourism can cause problems.For example，too many tourists can crowd public places that are also enjoyed by the inhabitants of a country.If tourists create too much traffic，the inhabitants become annoyed and unhappy.They begin to dislike tourists and to treat them impolitely.They forget how much tourism can help the country's economy.It is important to think about the people of a destination(目的地)country and how tourism affects them.Tourism should help a country keep the customs and beauty that attract tourists.Tourism should also advance the well being(health and happiness)of local inhabitants.
Too much tourism can be a problem.If tourism grows too quickly,people must leave other jobs to work in the tourism industry.This means that other parts of the country's economy can suffer.
On the other hand,if there is not enough tourism，people can lose jobs.Businesses can also lose money.It costs a great deal of money to build large hotels，airports，air terminals，first－class roads，and other support facilities(设施)needed by tourist attractions.For example，a major international－class tourism hotel can cost as much as 50 thousand dollars per room to build.If this room is not used most of the time，the owners of the hotel will lose money.
Building a hotel is just a beginning.There must be support facilities as well，including roads to get to the hotel，electricity, sewers(阴沟)to handle waste，and water.All of these support facilities cost money.If they are not used because there are not enough tourists，jobs and money are lost.
21.Which of the following has most probably been discussed in the paragraph that goes before the passage?
A．It is extremely important to develop tourism.
B．Building roads and hotel is essential.
C．Support facilities are highly necessary.
D．Planning is of great importance to tourism
22．Too much tourism can cause all these problems EXCEPT ______.
A．a bad impact on other industries B．a change of tourists' customs
C．overcrowdedness of places of interest D．pressure on traffic
23．Not enough tourism can lead to ______.
A．an increase of unemployment B．a decrease in tourist attractions
C．the higher cost of support facilities D．a rise in price and a fall in pay
24．It is good for local people to be well aware that tourism will ________.
A．use up a large amount of water B．weaken their economy
C．help establish their traditions D．help improve their life
