"Understanding the immune system is understanding the key to unlocking new cancer therapies."

To talk about painting is not only difficult but perhaps pointless too.

"We are all of us made by what we have lost as much as what we have gained."

成功的关键是永不停止学习。

感谢所有支持我的人，你们的爱是我最大的动力。

To understand a sentence means to understand a language.