题目内容：

Electric bicycles run on battery-operated(用电池发动的) motors. More and more people like this type of bikes________their speed and quality.

They were_______made in 1980s in China, but the selling was not very good. Today, thanks to(多亏了) improvement(改进) on the quality of the batteries, the electric bikes sell ______. There are more than 100 electric bicycle producers in China and________of such bicycles have been produced. Japan is________large producer of such bicycles in the world.

Now China is one of the_________producers of electric bicycles in the world, and lots of people have_____this kind of bicycles.

Such bikes are quick, safe and_______to operate,________their batteries still have shortcomings(缺点). They weigh more than 10 kilograms. Their service life is less than two years and they________500 yuan each.

1.A. because    B. because of    C. for    D. as

2.A. at first    B. first    C. the first    D. at firstly

3.A. good    B. bad    C. well    D. badly

4.A. thousand    B. two thousand    C. two thousands    D. thousands

5.A. another    B. other    C. others    D. the other

6.A. largest    B. smallest    C. bigger    D. fewest

7.A. bought    B. brought    C. broken    D. bright

8.A. hard    B. interesting    C. easy    D. boring

9.A. but    B. /    C. so    D. and

10.A. pay    B. cost    C. spend    D. worth