一、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选项。
1. It is such wonderful advice that I would be glad to take it without a word.
A. a B. / C. an D. the
2. We often climb mountains Sunday morning to keep ourselves healthy.
A. in B. at C. to D. on
