Why did Gao immigrate to America?

Gao has a distinguished family background. Grandpa Gao Jingde is the president of Tsinghua University, an academician of China Academy of Sciences and an electrical engineer. Grandpa Zhang Wei is the founder of Shenzhen University, an academician of China Academy of Engineering and Academy of Sciences, and a scientist proficient in four languages. Uncle Zhang Keqian is a famous scientist in physical electronics and optoelectronics, professor Tsinghua University and doctoral supervisor. My mother is a famous architect. Of course, Xiaokang has nothing to say.

I don't know if I got my green card from the United States, but according to American citizenship and immigration law, green card holders belong to foreigners who have neither American citizenship nor American citizenship. However, in the United States, they basically enjoy the same treatment as their own nationals and have no right to vote and stand for election. In other words, permanent resident green card holders do not need to give up their nationality.