Ⅱ. 单项填空(共15小题；每小题1分，满分15分)
21. (2012·合肥高二检测)The medical reform in that country proved to be _________ failure, but as we know, success often comes after _________ failure.
A. a; the B. a; / C. a; a D. /; /
22. It was very difficult to rescue the drowning boy in the sea. One moment the rescue workers _________ him but the next moment they _________.
A. caught sight of; lost
B. caught the sight of; lost his sight
C. caught sight of; lost sight of him
D. caught the sight of; lost their sight of him
23. You can _________ and start a new life; a small step at a time and happiness will follow.
