阅读下面的短文，掌握其大意，然后从各题所给的A、 B、 C三个选项中，选出一个最佳答案。
Once there was a man who could run fast. He was very proud 11 this and was always ready to show people how fast he could run.
One day a thief broke into his house, took some of his things and ran off as fast as he 12 . The man ran after him, shouting, “Hey! Stop! Don’t you know you can’t get away from me?” But the thief only ran faster. The man got 13 angry that he ran at his top speed. He was soon several miles away from his house.
He was still rushing along 14 he ran into a friend. “Why are you in such a hurry？” asked the friend. “I am trying to catch a thief.” said the man, who was very much out of breath. “But where is the thief?” asked the friend. “Miles and Miles behind!” said the runner, smiling with pride. “He 15 he could run faster than I can, but now, you see, he is quiet wrong.”
11. A. of B. in C. with D. off
12. A. would B. must C. could D. may
13. A. very B. quiet C. so D. rather
14. A. while B. though C. because D. when
15. A. thinks B. thought C. will think D. is thinking