单轴分枝
参考答案：
顶芽的生长始终占优势，这种分枝方式常形成明显的主杆。
A huge fire ______ last night and many houses were burnt down.
A．took place
B．took the place
C．in its place
D．took its place
区域活动的教育功能是通过（）来实现的。
A.时间
B.空间
C.内容
D.材料
