I've just come back from a holiday in the United States
我剛從美國度假回來。
May I ask where you come from?
請問貴處。
I am always tired when I come home from work.
我下班回家時總是很疲倦。
I come from China, a beautiful city!
我來自中國，一個美麗的.城市！
I come from a world full of life!
來自充滿鮮活生命的世界！