Ι.单项选择(本题15分)
1. He is _____ unusual writer. He can write _____ useful book.
A. a; the        B. a; a      C. the; an       D. an; a
2. Remember this, my son. ______careful you are, _______mistakes you will make.
A. The more ; the less          B. The less ; the fewer
C. The more ; the fewer         D. The more ; the more
3. --      do the children take art lessons ? 
   --Three or four times a week .