It can loosely be described as travel that takes place at regular intervals—often in an annual cycle—that may involve many members of a species, and is rewarded only after a long journey.

它可以比较粗略地描述成是发生在固定周期（这个周期通常是一年一次）的包含某一个物种很多成员的集体旅行，并且只有在长途旅行后才有回报。

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There are often two different types of health insurance you can consider buying: international travel insurance and student insurance in the country where you will be going.

通常你可以考虑购买两种不同类型的健康保险：国际旅行保险和你将要去的国家的学生保险。

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This focusing is the main reason that even relatively weak sounds in the ocean, especially low-frequency ones, can often travel thousands of miles.

正是由于这种集声，即使是海洋中相对微弱的声音，尤其是低频声音，也能传播数千英里。

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As part of the Department's American Music Abroad Program, the groups will travel to countries not often visited by American jazz musicians, in such regions as Africa,Asia,Europe, Latin America and the Middle East.

VOA: standard.2009.12.25

They are in their early 20s and often travel to Belfast for a night out in the Kremlin.

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Mr Cable acknowledged the seven companies - which mainly operate in the mining and extractive sectors - faced "unique challenges" in attracting more women since their line of work often involved regular travel and projects in "remote areas of the world".

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In addition to the cost advantages (travel companies often purchase tickets in bulk and can pass along savings) a tour company may employ area experts that know the best places to sleep and eat.

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