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！