美国有线新闻 CNN 英国启动脱欧进程 两年之后正式退出欧盟（在线收听）

We're talking about the Brexit, the British exit from the European Union. The E.U. has been around for decades. It's a political and economic partnership of 28 European Countries. Last June, Britain's voted 51.9 percent to 48.1 percent to separate from the E.U., potentially leaving 27 countries in it.

One major issue in Britain's decision was immigration. A majority of voters wanted Britain itself, not the E.U., to set British immigration rules. Another issue was the economy. Those who wanted to leave felt that Britain could do better business without European Union rules.

Britain was and is deeply divided over the vote. But the nation's prime minister, Theresa May, has said Brexit means Brexit. And now, she's just one day away from formally triggering Article 50. That's part of the European Union agreement.

What Article 50 does is begin the two-year process to separate Britain from the E.U. Two sides have to agree on the terms of their division. Why would something like this take so long? One reason is paperwork.

NINA DOS SANTOS, CNN INTERNATIONAL CORRESPONDENT: At the heart of Europe, five floors down, on five miles of shelving, thousands upon thousands of containers, row after row of red tape that Brexit supporters want Britain to leave behind.

Here in the archives of the Council of the European Union, you get an idea of the sheer scale of the paperwork that's involved with being a member of the E.U. Each of these boxes contains hundreds of legal documents, various texts and policy papers. And as the U.K. leaves, well, it will have to decide which ones it wants to keep, and which ones it wants to lose.

But for all the millions of words stored in Brussels, only 255 are needed to start that decision-making process. The five brief paragraphs of Article 50 provide the blueprint for exiting the European Union. With everyone watching, both the E.U. and the U.K. are hoping for a speedy harmonious conclusion, so that the writing at different floors in agreements that will eventually line these shelves can begin.

Nina Dos Santos, CNN, Brussels.