A:30°
B:60°
C:90°
D:120°
He is organized and is often . I hope he will have more at his business.
“春种一粒粟,秋收万颗籽”,一棵参天大树也是由一颗种子发育来的,其实是因为种子中包含有发育成一株完整植物的( )
计算2lg2+lg312lg36-lg12+log487×25