川普政府进一步限制合法移民：所有绿卡申请者都得回国通过领事申请

https://www.nbcnews.com/news/us-news/visa-holders-green-cards-return-home-country-trump-rcna346546

Non-immigrant visa holders must return to home countries to apply for green cards, Trump administration says

In a typical year, 1 million people apply for green cards and half of those apply from within the U.S. to change their status while they are living here, a former USCIS official said.