free trade agreement （FTA）自由貿易協定
The revised free trade agreement (FTA) between South Korea and the United States will take effect later this week, Seoul's trade ministry said Monday.
The two sides would exchange a written notification Tuesday that they domestically completed legal and procedural requirements for the implementation of the revised free trade deal, according to the Ministry of Trade, Industry and Energy.
Seoul and Washington launched negotiations on the revised FTA in January, and reached an agreement, in principle, in late March. The South Korean parliament ratified the revised accord earlier this month.
The Seoul ministry said South Korea and the United States rapidly amended the trade pact to reduce instability and stabilize trade and investment between the two countries.
The negotiations were launched as Washington demanded the amendment of its FTA with South Korea, which came into force in 2012.
take effect = come into force 生效；起作用
written notification 書面通知
in principle 大體上，原則上
trade pact 貿易協定
reduce instability 減少不穩定
Amendment 修正案 （Second Amendment to the United States Constitution）
China and Australia have signed a landmark free trade agreement that follows about a decade of negotiations.