The ruler is under the book.
—How about the book you are reading?—Good indeed. It many problems we have come across in our study.
在地图中A、B两地之间的图上距离是2厘米,实地距离是2千米,则该地图的比例尺是( )
为研究植物细胞质壁分离现象,某同学将某植物的叶表皮放入一定浓度的甲物质溶液中,一段时间后观察到叶表皮细胞发生了质壁分离现象.下列说法错误的是( )