Nature has a prefect system for recycling water. Water is used again and again .It falls as rain. -1- it goes one of three places. It might seep slowly through the soil -2- it soaks through into the natural reservoirs -3-. It might disappear into the air by -4- quickly. It might -5- into streams to rivers and to the oceans.

There is a problem -6- this recycling system. It is a balance that can be easily -7- by people. Nature's recycling system can work well -8- people work with the system-not -9- it. Some ways that people -10- with nature are easy -11-. Dirty sewagewater from homes and factories must not -12- with drinking water. People would get sick from drinking dirty water.

-13- other ways that people hinder nature. Some of these ways are not so easy to understand. -14-, a marshy bog may not be good for everything, but it -15- an important purpose. The soft, wet soil of a bog -16- water to reachthe underground reservoirs. What happens to the balance of nature if the bog is filled in? Many housing development projects have been built -17- marshes once were. The -18- of the houses are likely to have problems. They are likely to -19- water, to flood in -20- seasons. Huge storm sewers are built to carry away with the water from wet areas. These huge pipes prevent wet basements in the houses of teh community.

1. [A] Therefore[B] Then [C] Consequently [D] Nevertheless

2. [A] because　[B] if [C] after[D] as

3. [A] in underground　 [B] below underground [C] underground　[D] undergroundly

4. [A] evaporating [B] being evaporated [C] having been evaporated [D] being evaporated

5. [A] run down [B] run away [C] run off　[D] run through

6. [A] of　 [B] with [C] through　[D] from

7. [A] upset[B] created [C] discovered　 [D] invented

8. [A] only before　[B] unless [C] although [D] only if

9. [A] by　 [B] for [C] over [D] against

10. [A] accord　 [B] concern [C] interfere[D] intervence

11. [A] to be understood [B] understanding [C] to understand[D] being understood

12. [A] separate [B] clean [C] mix　[D] filter

13. [A] There are[B] They is [C] These are[D] Those are

14. [A] To start with[B] To name just a few [C] For example　[D] In contrast

15. [A] produces [B] serves [C] maintains[D] keeps

16. [A] forbids　[B] discourages [C] prevents [D] allows

17. [A] there[B] where [C] which [D] what

18. [A] basis[B] base [C] basic [D] basements

19. [A] come up with [B] fill up with [C] disagree with [D] finish with

20. [A] dry　[B] snowy [C] rainy[D] misty