We choose to go to the moon in this decade and do the other things, not because they are easy but because they are hard.

我们选择在这个十年内飞向月球以及做其他的事不是因为它们容易，而是因为它们很艰难。

youdao

There were three questions. The first two were relatively easy but the third one was hard.

有三个问题。头两个相对容易，第三个困难。

《牛津词典》

But sugar additives are not easy to identify and are hard to avoid.

但是糖类添加剂不容易被识别，而且很难避开。

youdao

Frost is not after "easy gold" but rather hard-earned wages.

弗罗斯特不追寻这些轻易得来的金钱而是实在地挣钱。

耶鲁公开课 - 现代诗歌课程节选

That's an important observation, and as we get to the part of the course we talk about computational complexity, you'll see that what we really care about is not how efficient the program is on easy problems but how efficient it is on hard problems.

我们已经学习了这门课程的一部分了，我们要开始认识到,计算的复杂度这个概念，你会学习到我们在乎的并不是,算法在简单问题上的工作效率,而是解决复杂问题的效率。

麻省理工公开课 - 计算机科学及编程导论课程节选

It's not the case that for Hannibal, choosing the easy pass to attack through, strictly dominates choosing the hard pass, but it is the case that there's a weak notion of domination here.

对汉尼拔而言,选择平坦之途入侵并不是,严格优于选择崎岖之途的,但是在这种情况下有一个弱优势

耶鲁公开课 - 博弈论课程节选

Its hard to explain but easy to demonstrate.

FORBES: Is Seeking Edge Thinkers

Customer loyalty is hard to come by but easy to squander.

FORBES: Apple Stores Lose Appeal, Need Shot Of Starbucks

In the following days, the trip became less hard, but it never became easy.

WSJ: Hiking the Tour du Mont Blanc