题目内容：

根据提示将下列句子进行升级训练

1.The local people didn't know the secret until the under- ground treasure was unearthed.(把 until从句提到句首，用倒装结构)

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2.Someone requested that a return ticket(should) be booked right away.(用 It is requested that句式)

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3.What should we consider before we decide to travel abroad？(用短语take...into consideration替换动词 consider)

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4.Living with host families gives them the chance to learn more about the new culture. In the families there may be other college students.(用非限制性定语从句把两个简单句合并为一个复合句)

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5.I came to live and study in a completely strange city for the first time.(用It is the first time改写该句)

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6.It is more meaningful to try getting around the world， but not to say meaningless words.(用 instead of改写该句)

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