题目内容
只有在移动闭塞系统部分或全部故障(即系统瘫痪)的情况下，后备系统才以自动或人工的方式启动，根据设计要求及线路的实际情况，也可以将（）系统作为移动闭塞系统的1个子系统，参与正常运营。
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The author uses 3 consecutive________to attract the readers attention.
College is designed to be a time of personal ________ and ________.
In this text, the author mainly talks about the developmental changes that college students would often go through during their college years.
How to define "developmental changes"?
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