英语“必由之路“怎么表达？谢谢

必由之路:
1. the road one must follow or take
2. the only way
3. the only way leading to

This may be the only solution for the surplus labour in the countryside.
这恐怕是必由之路。
The surest way to be happy is to be busy.
繁忙是通往幸福必由之路。
REFORM IS THE ONLY WAY FOR CHINA TO DEVELOP ITS PRODUCTIVE FORCES
改革是中国发展生产力的必由之路
Perseverance is the only road to success.
坚韧不授乃成功必由之路。
If anyone asks why a Communist should strive to bring into being first a bourgeois-democratic society and then a socialist society, our answer is: we are following the inevitable course of history.
若问一个共产主义者为什么要首先为了实现资产阶级民主主义的社会制度而斗争，然后再去实现社会主义的社会制度，那答复是：走历史必由之路。
Practice has proved that building socialism with Chinese characteristics is a road of development that is in accordance with the fundamental interests of the Chinese people, and also the only road which can effectively promote human rights in China.
实践证明，建设有中国特色社会主义是一条符合中国人民根本利益的发展道路，也是一条