笔试部分：
I. 单项选择
1. ______ they grow they make sure that what is left in the ground after harvesting ___________ a natural fertilizer for the next year's crop.
A. Whatever; become B. Whichever; become
C. Whatever; becomes D. Whichever; becomes
2. — What about the protection?
— Let's keep the surface ______ dirty by putting a cover over it.
A. far from B. free from C. apart from D. away from
3. I have offered to paint the house ______ a week's accommodation.
A. in exchange for B. in the event of C. by means of D. in place of
4. Much of the power of the trade unions has been lost. ______, their political influence is still very great.
A. As a result B. As usual C. Even so D. If so
