— A car came along suddenly and came fast towards him.
A:turned on
B:showed up
C:passed by
如图,一束光在空气和玻璃两种介质的界面上发生了反射和折射,请判断: ____是入射光线,折射角为 ____°,玻璃在 ____(AB面的左方/AB面的右方/CD面的上方/CD面的下方)。
下列命题中,真命题的是( )
下列有关分类单位的说法正确的是( )