下列对蒸腾作用理解不正确的是( )
A:水分以水蒸气的形式从叶表皮的气孔散发到大气中
B:移栽树木时应多保留树叶,增大其蒸腾作用
C:为植物体各细胞输送水分和无机盐提供动力
D:能改变周围环境的温度和湿度
一个圆的半径是2厘米,这个圆的周长是____厘米,面积是____平方厘米.
历史年表制作年代尺是历史学习的有效途径之一,它能将复杂的历史发展进程较直观形象地展示出来。下面是中外历史某时期年代尺示意图(注:B.C.是公元前的英文缩写)。
从方框中选择适当的单词完成短文。
What's this on the table? It is a ____ of my new classroom. ____ at the picture. ____ can you see ____ the classroom? I can see a ____ desk in the front of the classroom. Some books are ____ the desk. I can see two white ____ , too. There are____ colored chalks (彩色粉笔n them. ____ is the broom (扫帚)? It’s ____ the door. I like this new classroom.