When was the slogan "Three People's Principles Unify China"? When did "one country, two systems" unify China?

At present, Taiwan Province Province has not returned to the embrace of the motherland, and both Hong Kong and Macao have returned. Hongkong returned to China in July1997; Macao returned to China on February 20th 1999. The problems in Taiwan Province Province are completely different from those in Hong Kong and Macao-Hong Kong and Macao were colonized by foreign countries, while Taiwan Province Province was the internal affairs of the country when the Kuomintang retreated to Taiwan Province Province in 1949 and established political power, resulting in division.

Now the two sides of the strait have realized the "three cross-strait links"