A:My father goes to work on Saturdays.
B:My father plays football on Saturdays.
已知图形:①等边三角形,②平行四边形,③菱形,④圆.其中既是轴对称图形,又是中心对称图形的有( )
—How about the book you are reading?—Good indeed. It many problems we have come across in our study.