如果你不固执，就会过早放弃试验。如果你不灵活，就会头撞南墙，而无法另辟蹊径解决当下难题。
If you're not stubborn， you'll give up on experiments too soon. And if you're not flexible， you'll pound your head against the wall and you won't see a different solution to a problem you're trying to solve.
