十

Well, son, that's why it's important to learn a second language.

It is加形容词加to do something是英语中一个重要的形容词，句型十分常见，能够这样用的形容词处important why我们学过的，还有aeasy,difficult等，表示做某事是重要，容易，困难的，例如:

It's difficult for me to study math对我来说学习数学很难。