如果你不固执，你会过早放弃实验。如果你不灵活，你会把头撞在墙上，看不到你试图解决的问题的不同解决方案。
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.
