）大学英语四级阅读理解试题及答案（四） 十六Trees should only be pruned when there is a good and clear reason for doing so and , fortunately,the number of such reasons is small. Pruning involves the cutting away of obergrown and unwanted branches, and the inexperienced gardener can be encouraged by the thought that more damage results from doing it unnecessarily than from leaving the tree to grow in its own way.First, pruning may be done to make sure that trees have a desired shape or size. The object may
