《the persuit of happiness》 开头的音乐是什么

中文译名《当幸福来敲门》。
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the persuit of happiness the persuit of happyness a father's way 歌词有谁知道! persuit 是什么意思？ the summary of The Merchant of Venice The phantom of the operadint the colour of the night the principle of the telescope The question of the QQ: the Lord of the Rings the center of the world