6×8=____ 2×8=____ 8×8=____
813+lg5+lg20-eln2=____
读下面甲、乙两图,回答下列小题。
It's reported that people throw plastic bags along this street every day.
如图,在Rt△ABC中,∠C=30°,以直角顶点A为圆心,AB长为半径画弧交BC于点D,过D作DE⊥AC于点E.若DE=a,则△ABC的周长用含a的代数式表示为____ .
日本领土组成中的四个大岛,纬度最高的是( )