四、完形填空。
In a Physics class，the teacher asked the students，"Why do we have brakes in our car?" A student got up and replied，"Sir，to 1 the car." Another student replied，"To reduce and control the 2 of the car." Another said，"To 3 the collision(碰撞事故)." Soon，all the students began to give similar answers. So，the teacher 4 to answer the question himself. He said，"I appreciate all of your answers. 5 I look in this way—the brakes in the car allow us to make it run faster." Hearing this，there was complete 6 because no one had imagined this answer. The teacher continued，"Let's assume(假定) our car to have no brakes. How 7 are we ready to drive our car? It is the brakes in the car that give us 8 to drive faster and reach our destination."
All the students got confused. They 9 thought of that. The teacher smiled and continued，"10，there are many such brakes in our life. Our parents，teachers and friends ask us about the direction we want to follow，our progress or decisions in life. We are likely to 11 their questions or difficult situations as brakes that slow down our pace. But what if we see them as the catalyst(催化剂) that allows us to take risks while ensuring that we protect ourselves? Sometimes，we have to stop or even step 12 so that we can take a giant leap. It is because of such questions or situations that we are able to 13 where we are today. Without these brakes we could slip，lose our direction or be the 14 of unfortunate accidents. Therefore，we need to understand that brakes in our life are not 15 to push us back or bind(约束) us but to help us move forward faster than before so that we can reach our destination quickly and safely."
1. A. drive
B. check
C. manage
D. stop
2. A. speed
B. size
C. space
D. shape
3. A. cause
B. repair
C. avoid
D. produce
4. A. forgot
B. decided
C. promised
D. preferred
5. A. But
B. Until
C. Unless
D. Because
6. A. sleep
B. breath
C. silence
D. trouble
7. A. clearly
B. far
C. carefully
D. fast
8. A. time
B. courage
C. greed
D. pain
9. A. never
B. always
C. often
D. sometimes
10. A. Suddenly
B. Unluckily
C. Similarly
D. Generally
11. A. create
B. answer
C. raise
D. view
12. A. down
B. back
C. away
D. forward
13. A. help
B. leave
C. reach
D. explore
14. A. suspects
B. witnesses
C. winners
D. victims
15. A. meant
B. imagined
C. invited
D. refused

1~5. DACBA 6~10. CDBAC 11~15. DBCDA