现在，总结一下，在今天的课上，我们回顾了英语作为世界第一语言的流行背后的一些原因或因素。

Now, to sum up, in today's lecture, we have reviewed some of the reasons or factors that lie behind the popular use of English as the number one world language.

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回顾和总结。

Review and summarize.

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这张图片总结了整个的课程,目标，这是一课接着一课,作为课题的领域，今天我们将要回顾,全部的反应堆种类，它们现在都仍然存在的。

This is a slide that summarises the overall course objectives and this is lecture by lecture as topical areas. Today we're gonna review the overall reactor types that are presently in existence.

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