It isn't always easy to separate the wheat from the chaff.

分清好坏并不总是容易的。

《柯林斯英汉双解大词典》

Learning to play the piano isn't easy. You have to work at it.

学弹钢琴不容易，你非得下功夫不可。

《牛津词典》

If saving energy is so easy and profitable, why isn't everyone doing it?

如果节约能源是如此容易和有利可图，为什么不是每个人都这样做呢？

youdao

It isn't the case that defending easy dominates defending hard.

防守平坦之途并非优于防守崎岖之途

耶鲁公开课 - 博弈论课程节选

If you think this class is going to be easy, I think it isn't actually an easy class. It's actually quite a hard class, but I think I can guarantee it's going to be a fun class.

你要是认为这门课挺简单,这不是轻松的课,事实上它有点难,我保证这门课一定很有趣

耶鲁公开课 - 博弈论课程节选

Well in C and other languages that we'll see this semester, you use what's called the for loop, and this as syntax isn't quite as straightforward but once you know what to look for, it's very easy to understand.

在C语言和一些我们这学期将要接触的编程语言中，你将会用到所谓的for循环，也许作为一种语法规则，它看起来不是那么的通俗易懂,但是你一旦知道曲中奥妙，就不难理解了。

哈佛公开课 - 计算机科学课程节选

I've actually tried operating that from my days when I was working as part of a train company and it isn't as easy as it sounds.

BBC: Track Record forum: George Muir

But it isn't easy and it's never a sure thing.

FORBES: Magazine Article

Delmonico favors calling the disorder hypersexuality, and notes that it isn't easy to diagnose: It takes at least two or three hours of discussion with a patient to determine if he or she is hypersexual.

FORBES: The Shadowy Science Of Sex Addiction