站在太阳下,就要懂得什么是坚强.这句话用英语怎么翻译?

When you are standing under the sun then you need to know what is strong.

Still standing beneath the Sun, you ought to realize the true meaning of toughness.

我比较同意 splashchaos 的答案 'you ought to realize the true meaning of toughness'.
无论是 "Strong" 或 "Toughness", 它并不代表 "坚强" 只能是 "强" 或" 强硬"
"Be strong" = 坚强
My answer:
When you stand beneath the sun, you need to understand what it means to be strong/tough.