Look...In 2015, Biff steals the sports almanac and takes the time machine back to 1955, to give it to his younger self. 你们看...2015年，Biff偷了运动年鉴，然后拿了时光机器回到1955年，就为了把年鉴给年轻的自己。

But as soon as he does that, he changes the future, so the 2015 he returns to would be a different 2015, not the 2015 that Marty and Doc were in. 但一旦他这么做了，他就改变了未来。所以他回到的那个2015年就是个不一样的2015年，而不是Marty和博士在的2015年了。

This is Hot Tub Time Machine all over again. 这和《热浴盆时光机》完全一样。（热浴盆时光机：电影讲述三个好朋友回到幼年的滑雪场旅店，利用屋中的热浴盆时光机回到1987年）

If future Biff goes back to 2015 right after he gives young Biff the almanac, he could get back to the 2015 with Marty and Doc in it. 如果未来的Biff一把年鉴交给年轻Biff就回2015年的话，他就能回到有Marty和博士的那个2015年。

Because it wasn't until his 21st birthday that 1955 Biff placed his first bet. 因为，1955年的Biff是到了21岁生日的时候才赌了第一次。

Wait. Whoa, whoa. Is "placed" right? 等等，等等。用"赌了"不对吧？

What do you mean? 你是什么意思？

Is "placed" the right tense for something that would have happened in the future of a past that was affected by something from the future? 用"赌了"来形容本该在被未来某物影响的过去的未来发生的事情 时态对吗？

Had will have placed? 在未来的过去的未来赌了？

That's my boy. 干得漂亮。

Okay, so, it wasn't until his 21st birthday that Biff had will have placed his first bet and made his millions. That's when he altered the timeline. 好吧，1955年的Biff是到了21岁生日的时候，才在未来的过去的未来赌了第一次赚了百万。那时候他才改变了时间线。

Yeah, but he had will haven't placed it! 没错，但他没有在过去的未来的过去赌！

What? ! 什么？！

Unlike Hot Tub Time Machine, this couldn't be more simple. 和《热浴盆时光机》不同，这个简直太简单了。

When Biff gets the almanac in 1955, the alternate future he creates isn't the one in which Marty and Doc Brown ever use the time machine to travel to 2015. 当Biff在1955年拿到了年鉴，他创造的未来就不是Marty和Brown博士会用时光机器去的2015年。

Therefore, in the new timeline, Marty and Doc never brought the time machine...-W-Wait. 因此在新的时间线里，Marty和Doc从来没有带过来那个时间机器...-等... 等等。