Paraphrasing (20th paragraph)
Text
Many supporters of trade have opposed unilateral liberalization by pointing out that although open domestic markets are important, it is preferable to open markets everywhere at once. That is certainly true. But it is also true that trade negotiations cannot force countries to drop their trade barriers; nations open up only when the domestic political atmosphere is right. Trade agreements may be a useful way to "lock in" the benefits of free trade, but they have never been the primary impetus for it. Instead, developing countries are embracing free trade because they have observed the benefits it brings. The most effective way for Europe to open foreign markets is to lead by example. And even the staunchest multilateralist should agree that in a world where trade agreements are subject to popular scrutiny, educating the public about the virtues of open domestic markets must be a top priority.
The main idea of the paragraph
Although some people prefer that the markets of both EU countries and other countries are opened at the same time, the most effective way to have the markets of other nations opened is to show them the benefits of free trade, and the EU can lead by example in this regard.
虽然有些人更愿意看到欧盟和其他国家的市场同时开放，但是，要让其他国家打开其市场的最有效的方法是向他们展示自由贸易的好处，欧盟可以在这个方面以自己的榜样作用来带个头。
句子分析
But it is also true that trade negotiations cannot force countries to drop their trade barriers; nations open up only when the domestic political atmosphere is right.
在此句中：
1）两个并列分句之间通常由并列连词连接，但有时候也可以不用并列连词、而采用分号来连接两个并列分句，本句就是个例子。在本句中，分号连接了两个并列复合句“it is also true that trade negotiations cannot force countries to drop their trade barriers”和“nations open up only when the domestic political atmosphere is right”。
2）另外，在前一个并列复合句中，“that”引出的从句“that trade negotiations cannot force countries to drop their trade barriers”作句中的实际主语，“it”作形式主语；在后一个并列复合句中，“when”引出的从句“only when the domestic political atmosphere is right”作时间状语，修饰谓语动词“open up”
词语解释
lock in
to do something so that a price, offer, agreement etc cannot be changed 使…固定，e.g.
Sell your stocks now to lock in some of the gains of recent months.
现在就把你的股票卖了，这样你近几个月赚的钱就可以真正到手了。
