单项选择题
A．planting many trees and fertilizing them B．collecting seeds from strong, slow growing trees C．selecting the seeds of the fastest growing trees D．feeding them high-energy plant foods
A. I prefer the leather one B. What do you like C. It looks warmer D. clerk E. It sounds nice F. price tag G. to try it on H. Which one do you like better
A．audience B．researchers C．veterinarians D．mathematicians