In my opinion Everything works, there is a barrier to matter. We have lessons to learn experience. When we see this, we will have immunity and can solve this problem, pass by!
In my opinion, All work shall have a common drawback. A lesson to be learned. The experience When we see this event We will not have immunity The solution is to go well.
In my opinion. Work everything has obstacles are common. The lesson for us to learn, experience when we see this, we will have immunity, and can solve this problem to work out fine.