Ⅰ.单项填空
1. Nowadays, skiing ______ being a sport, has become a big industry and a notable feature of leisure culture.
A. except for B. apart from
C. far from D. due to
2. Clean air is and will be a luxury(奢侈品) in many cities unless tough measures ______ to better the present situation. (2014·长沙一中月考四)
A. take B. will be taken
C. are taken D. have taken
3. Brick walls, when properly ______， can last at least one hundred years.
A. being built B. building
C. to build D. built
4. — Did Tom visit you alone yesterday?
— No, he was ______ by his classmate.
