More than two trees are planted in our neighbor-hood every year.
A:hundred
B:hundreds
C:hundreds of
D:hundred of
作图题:如图,已知O是坐标原点,B、C两点的坐标分别为(3,﹣1)、(2,1).
(1)以O点为位似中心在y轴的左侧将△OBC放大到两倍(即新图与原图的相似比为2,画出图形);
(2)分别写出B、C两点的对应点B′、C′的坐标.
要反映某市一周内每天最高气温的变化情况,宜采用 ( )