二. 单项选择（每题1分，满分15分）
21. If any man here does not agree with me, he should _______ his own plan for improving the living conditions.
A. put on B. put out C. put down D. put forward
22. So difficult ______ it to work out the problem that I decided to ask Tom for advice.
A. I did find B. did I find C. I have found D. have I founded
