问题详情

Treesbecomeunhealthyifthegardener？？______.
A．tohelpsawoundtodry
B．tocoversaroughsurface
C．damagessomeofthesmallsidebranches
D．allowstoomanybranchestogrowinthemiddle
请帮忙给出正确答案和分析，谢谢！