It's q____ convenient to travel by high-speed train.
(2016•青岛)读图,南极洲简图,下列关于南极地区的叙述,正确的是( )
(参考数据:sin58°=0.85,cos58°=0.53,tan58°=1.60)
设NA为阿伏伽德罗常数的值.下列说法正确的是( )