Day 9——Social problems 社会问题（听力部分）

Spot dictation

经典题目操练：(听力教程P43)

The                (1) in rocket theory 40 years ago showed that liquid-fuel rockets were far superior in every respect to the skyrocket with its              (2) solid fuel, the only kind of rocket then known. However, during               (3), large solid-fuel rockets with solid fuels about as                (4) as liquid fuels have made their appearance, and it is a favorite layman’s question to inquire which one is “better”. The question is                 (5), one might as well ask whether a gasoline or a diesel engine is “better”. It all                  (6) the purpose. A liquid-fuel rocket is complicated, but has the advantage that it can      

           (7) beautifully. The burning of the rocket engine can be stopped      

            (8); it can be reignited when desires.                  (9), the thrust can be made to vary by adjusting the speed of the fuel pumps. A solid-fuel rocket, on the other hand, is                  (10) in construction, though hard to build when a really                   (11) is desired. But once you have a solid-fuel rocket, it is ready for action at very                   (12). A liquid-fuel rocket has to be fueled first and cannot be held                  (13) for very long after it has been fueled. However, once a solid-fuel rocket has been ignited, it will                    (14). It cannot be stopped and reignited whenever desired,                      (15), it could conceivably be stopped and reignited after a pre-calculated time of burning has elapsed and its thrust cannot be                      (16). Because a solid-fuel rocket can be kept ready for a long time, most military missiles employ solid fuels, but manned spaceflight needs the fine adjustment that can only                    (17) by liquid fuels. It may be added that a liquid-fuel rocket is an expensive device; a large solid-fuel rocket is,    

                     (18), cheap. But the solid fuel, pound per pound, costs about                 (19) as the liquid fuel. So you have, on the one hand, an expensive rocket with a cheap fuel and on the other hand a                  (20) cheap rocket with an expensive fuel.

----------------------------------------------------------------------------------------------------------------

答 案

Spot dictation:

1. great advance

2. weak

3. the last decade

4. powerful

5. meaningless

6. depends on

7. be controlled

8. completely

9. In addition

10. rather simple

11. large size

12. short notice

13. in readiness

14. keep burning

15. that is

16. varied

17. be provided

18. by comparison

19. 10 times

20. comparatively