three forces的用法和樣例：
例句
- We all understand that over-development of any forces will result in disaster.
因為我們都了解，任何一股力量如果過度發展，都會有災難。 - I started thinking about the fact that I stand in the middle of two opposing forces in the Negro community.
我開始考慮這麽一個實際情況，即我恰恰站在黑人社會兩股對立的力量中間，滿足於現狀的那股力量由兩類黑人組成。
