A:根
B:茎
C:叶
D:花
在平面直角坐标系中,O为原点,点A(4,0),点B(0,3),把△ABO绕点B逆时针旋转,得△A′BO′,点A、O旋转后的对应点为A′、O′,记旋转角为ɑ.
如图甲为显微镜下观察洋葱鳞片叶内表皮细胞临时装片的几个视野,请据图回答问题:
Our head teacher is kind to us and she is like our mother, ____.