Red giant stars do not become white dwarf stars abruptly; the process takes more than fifteen hundred years.

题库:综合类 类型:最佳选择题 时间:2017-07-03 03:11:38 免费下载:《单项选择》Word试卷

Red giant stars do not become white dwarf stars abruptly; the process takes more than fifteen hundred years.
A.suddenly
B.in unison
C.prematurely
D.accidentally

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