Your timing made you and your partner the most infamous bank robbers in the west.
你的时机把控，让你和你的搭档成为了西方最臭名昭著的银行劫匪。
Now, you'll need to use that timing to help you break out of jail.
现在，你要等待时机越狱。
At the appointed time, you'll be walking in the yard near the electric fence.
在约定的时间，你要走到院子的带电栅栏旁。
Your partner will flash you the signal, and exactly 45 seconds later, short out the fence circuit.
你的搭档将会给你发出信号，并且在45秒后电栅栏将会短路。
It'll automatically restart after a second or two, but as long as you move fast, you'll be home free.
再过一两秒，电栅栏的电路又会自动重启，但是只要你动作迅速，你就可以越狱成功。
And then you notice, to your horror, that your watch is broken, and there's no time to fix it.
之后，你惊恐的发现你的手表坏了，也没有时间去修它。
The signal is coming, and if you make even a small mistake in counting off 45 seconds, you'll get fried.
但是信号来了，如果你在数这45秒的时候，只要犯了一点小小的错误你将会被电焦。
Searching your pockets, you find something that might help:
翻了一下口袋，你发现了一些可能帮助到你的东西：
a lighter and two fuses you made earlier in the prison work program.
你在之前监狱劳改中做的一个打火机和两条保险丝。
Each fuse is a length of flammable twine, built to be lit on either end and burn for precisely one minute.
每一节保险丝都是一段易燃的线，可以在点燃任何一端的情况下燃烧一分钟。
The problem is that even though the fuses look uniform, they don't burn evenly,
但问题是，即使这些保险丝看起来很均匀，但它们并不能均匀地燃烧，
so if you cut one in half, for example, one side might burn longer than the other.
所以如果你把它剪成两段，一段可能会比另一段燃烧地时间长。
Your partner is going to give the signal any minute, and you'll have to make your move.
你的搭档会在任何时间给你信号，你不得不行动。
How can you use the fuses and lighter to time exactly 45 seconds?
你怎么能用打火机和保险丝准确地计算45秒呢？
Pause the video to figure it out yourself.
请先暂停视频，自己思考一下答案。

Answer in 3. Answer in 2. Answer in 1.
答案3秒后出现。答案2秒后出现。答案1秒后出现。
The length of the fuse may not tell you anything,
保险丝的长度并不会帮助你解决任何问题，
but you do know the fuses take exactly 60 seconds to burn from end to end.
但你知道保险丝从一段燃烧到另一段正好是60秒。
Here's the key insight:
这是解决问题的关键：
If you start a fuse on one side and it burns for 30 seconds, there'll still be 30 seconds of fuse left.
如果你点燃保险丝的一段并且燃烧了30秒，那么剩余的保险丝也会燃烧30秒。
If you had started it from the other end, it would've reached the exact same spot in thirty seconds.
如果你从另一段点燃，那么在30秒的时候将会到达和刚才一样的点。
That means that if you lit it from both ends simultaneously, it would burn out in precisely 30 seconds.
这就意味着如果你同时点燃保险丝的两端，这条保险丝将会准确地在30秒的时候燃烧完。
But how will you time the last fifteen? That'll have to come from the second fuse.
但是剩下的15秒怎么办？这就要用到第二条保险丝了。
If it were a 30 second fuse, you'd be able to use that same trick again
如果这是一条30秒就能燃烧完的保险丝，你可以用同样的方法，
to double the burning speed and make it last exactly 15 seconds.
两头点燃就是正好地15秒。
And, you realize, you can shorten the second fuse by lighting one end of it at the same time as you light the first.
并且你发现你可以缩短第二条保险丝，在你点燃第一条保险丝的时候就点燃第二条的一端。
At the moment the first burns out, you'll be left with 30 seconds on the second fuse.
当第一条燃尽的时候，你会剩下一条可以在30秒烧完的保险丝。
Just when you've got this all figured out, you see the signal from your partner, and spring into action.
正好在你解决了问题的时候，你看到了搭档的信号，开始行动。
You gather the four ends of the two fuses and light three of them.
你把两条保险丝的三头点燃。
The moment the first burns out, you light the other end of the second fuse.
当第一条烧尽的时候，再点燃第二条保险丝的另一头。
When it flickers and dies, you know that exactly 45 seconds have passed, and the electric fence is dead.
当第二条也烧尽时，正好45秒过去了，此时电栅栏停止供电。
By the time it hiccups back to life, you're over the fence and home free.
当它再次通电时，你已经越过了栅栏并且越狱成功。