这项计划又困难又危险，但我们终于完成了。

The plan was difficult and risky, but we pulled it off.

youdao

在工科数学教学中加强应用教学既迫切，又困难。

It is urgent and difficult to reinforce the application-oriented teaching of mathematical application at present.

youdao

工程索赔在工程管理中既重要又困难，它是经验型的工作。

Construction claim, which is characterized by experience, is important and difficult.

youdao

I don't know how many kids, generation after generation, get in trouble because they do not remember the following fact.

我不知道有多少孩子,一代又一代,因为没有记住下面的内容而遇到困难

耶鲁公开课 - 基础物理课程节选

Once your programs get fairly complex, it becomes harder and harder to find things and to tweak things if you're not being organized.

一旦代码稍微复杂点,而你又不规范你的代码,那么你想找什么东西就很困难了。

哈佛公开课 - 计算机科学课程节选

And because you can't really know, it's difficult to make the right kinds of plans.

又因为你无法知道，要作正确的规划就困难重重。

耶鲁公开课 - 死亡课程节选