A:why
B:where
C:how
D:whe
下列自然资源中属于不可再生资源的是( )
①Mum hello family a thin girl your mother Mr Wang
②Is he a fat teacher? No,he isn't. He's a thin teacher.
古曰“民以食为天”,如今“食以民为天”;食品安全已成为当今社会热点.对以下叙述错误的是( )
ΔABC是边长为2的等边三角形,已知向量→a,→b满足→AB=2→a,→AC=2→a+→b,则下列结论正确的是
如图一束光从空气斜射入平行玻璃砖(入射角为50°)后,再折射入空气.
(1)图甲、乙两图中,符合光的折射规律的是图____ (选填“甲”或“乙”);
(2)光从玻璃斜射入空气中的折射角____ 50°(选填“大于”、“小于”或“等于”).