单项选择题 The theory has been championed for a number of reasons, but many current proponents point to the presence of methane on comets, meteors, and other lifeless planets as evidence that organic material is not needed to produce. A、envisionedB、demonstratedC、complementedD、advocated

单项选择题 镜片开槽机一般不适用于（）材料

单项选择题 2.单片机中不包括以下哪一逻辑部件（ ）。