Many Americans have been leaving their cars at home and riding to work on bicycles. Andy Clark is the leader of the League of American Bicyclists. His group supports bicycling for fun, fitness and transportation.
Clark says this is good news for the environment. He says riding a bicycle to work does not burn fossil fuel or creates dangerous pollutions. Experts say the effects are the most important on short trips. The Department of Transportation says fifty percent of Americans drive eight kilometers or fewer to work. Shorter car trips set out more pollution into the air for each kilometer drive. This is because the car engine will set out the harmful air when it warms up before it can work well.
James, a members of Congress (国会), is a strong supporter of bicycle use. He says cities, counties, state governments and state highway transportation agencies are planning the roadways of the future. They are creating roads and paths for bicycles in cities and between communities.
Last year, Portland, the Pacific Northwest city in the state of Oregon, had the highest percentage of bicycle users in the United States. Portland has been doing progressive city planning for many years to create special paths for bike riders.
What happened in America now according to the news?

A．Many Americans lost jobs now.

B．Many Americans prefer short trips.

C．There are more and more bicyclists now in America.

D．The pollution is getting worse and worse in America.

Where is Portland?
A. One  of the cities in the USA.    B. One of the counties in the USA.
C. One of the states in the USA.    D. A country in the northwest of the USA.
What does the underlined word “harmful” mean in the second paragraph? The closest meaning is “_______”.

A．polluted

B．dangerous

C．clean

D．foolish

What is the main idea of the passage?

A．Many Americans like bike-riding for fun.

B．Short car trips can reduce pollution.

C．American government suggests people riding bicycles.

D．Many Americans ride bicycles to support environment protection.