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The bike is one of the simplest yet most useful inventions in the world. What is the most urprising is that it was not invented 1, although the great inventor Lenardo da Vinci had drawn pictures for bikes 2 for flying machines and some other things. Those things were not produced  3  long after he died.

     A person riding a bike 4  very little energy to make it move, and there is no5  at all when he is riding one. Even so, in developed countries, most people don't go to work  6 bike. It is not because the bikes are expensive. It's because the number of 7 on the road becomes larger. It certainly becomes more   8  to ride a bike. As a result, more people put their bikes away and go to work in their cars, and 9 this way, the situation is made more serious. Perhaps the best way to make bike riding safer and more 10 is to create paths only for bikes, and to make it so difficult and expensive for drivers to ride to in their cars into the city that they will go back to use their bikes.

1. A. earlier         B. faster           C. later            D. cheaper

2. A. as for          B. and also        C. so that           D. not only

3. A. since          B. unless          C. until             D. so

4. A. costs          B. takes           C. spends           D. uses

5. A. pollution       B. air             C. environment      D. place

6. A. on            B. by             C. with             D. in

7. A. people        B. trains           C. cars              D. planes

8. A. safe          B. slow           C. boring            D. dangerous

9. A. in            B. with           C. by               D. on

10. A. wonderful     B. popular        C. helpful           D. excellent