我吃了苦头才明白，每天训练并不是保持健康的最佳方法。

I ___learned ___the ___hard ___way that training every single day is not the best way to get fit.

如果你忽视历史，很可能得通过艰难的方式吸取教训。

If you ignore history, you'll likely have to ___learn its lessons ___the ___hard ___way.

一些企业家宁愿通过艰难的方式行事，在没有外部投资者的情况下建立自己的企业。

Some entrepreneurs prefer to ___do it ___the ___hard ___way and build their businesses without external investors.