A:sin2﹣cos2
B:cos2﹣sin2
C:±(sin2﹣cos2)
D:sin2+cos2
-- ______ father took part in the charity activity in the neighbourhood yesterday?
-- Peter's.
图为细胞膜结构及物质跨膜运输示意图,下列有关叙述正确的是( )
世界最大的格陵兰岛属于( )