A:高浓度促进杂草衰老
B:高浓度抑制杂草生长
C:低浓度抑制杂草生长
D:高浓度促进小麦生长
如图,点A,B,C是⊙O上的点,AO=AB,则∠ACB= ____度.
_________ people like him because he thinks _________ of himself than others.