| Trees should only be pruned (修剪) when
there is a good reason for doing so. Many gardeners believe 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. The object may be to get a tree of the right height, and 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 causing wounds. A tree may grow healthier by removing the branches that are locking up the centre 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 (进入) f A. Pruning is necessary when there are unwanted branches. B. Damage is done to a tree if it is left to grow in its own way. C. Diseased or dead branches should be cut away if they are found to rub against each other. D. Growing side branches often prevent air from moving freely. [填空题]We should do all we can to protect wetlands to ensure that their functions and values will be preserved for______.
[单项选择]We should— when we want to glimpse inside the sun.
A. answer questions about its temperature B. translate the sounds into images C. know how gases inside ebb and flow D. measure the pitch 我来回答: 提交
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