Ⅱ. 单项填空（共15小题；每小题1分，满分15分）
从A、B、C、D四个选项中，选出可以填入空白处的最佳答案。
11. Some children prefer to spend much time reading，_________is really good for them.
A. as B. what C. which D. that
12. Now the population of the city is_________ that of ten years ago.
A. three times as large as B. as three times large as
C. three times as many as D. three times more than
13. —When will it be convenient for us to meet? Monday or Tuesday?
—___________. I will be busy the whole week.
A. Either B. Both C. None D. Neither
14. —You know the school very well.
—Yeah. I____ here for 15 years and I will work another 15 years.
A. had worked B. was working
C. have been working D. am working
15. Richard promised to come to attend the lecture, but till now he hasn't _________yet.
