文档介绍：厦门大学网络教育2015-2016学年第一学期
《英语2》课程复****题
I. prehension:
Passage 1
Trees should only be pruned (修剪) 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 overgrown 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 be to get a tree of the right height, and at the same time to help the growth of small side branches which will thicken its appearance or give it a special shape. Secondly, pruning may be done to make the tree healthier. You may cut out diseased or dead wood, or branches that are rubbing against each other and thus cause wounds. The health of a tree may be encouraged by removing branches that are blocking up the center and so preventing the free movement of air.
One result of pruning is that an open wound is left on the tree and this provides an easy entry for disease, but it is a wound that will heal. Often there is a race between the healing and the disease as to decide whether the tree will live or die, so that there is a period when the tree is at risk. It should be the aim of every gardener to reduce that risk of death as far as possible. It