费城：一座以历史闻名的城市 Philadelphia, also sometimes called Philly, is a big city on the Delaware River in the northeastern state of Pennsylvania.
航天器登月简史 Many years have passed since the first spacecraft landed on the moon in 1966.
费城：一座以历史闻名的城市 Philadelphia, also sometimes called Philly, is a big city on the Delaware River in the northeastern state of Pennsylvania.
航天器登月简史 Many years have passed since the first spacecraft landed on the moon in 1966.