I don't think you need to be sad to write a sad song.

"The essence of mathematics lies in its freedom."

I know what I can do, so it doesn't bother me what other people think or say.

恐惧是创造力最大的敌人。

机器人是一种被编程执行多种任务的设备，并且可以重新编程以执行其他任务。