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 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 diseaed 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 centre and so preventing the free movement of air.
One result of pruning is that an open wou因此从排油腔起沿着齿轮外缘至吸油腔的每个齿间的油压是不同的nd is left on the tree and this provides an easy entry for disease, but itis a wound that will heal. Often there is a race between the healing and the desease as to 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 which has b而随着产业转型升级的加速een pruned smooth and clean, for healing will be slowed d万事如意own by roughness. You should allow the cut surface to dry for a few hurs and then paint it with one of the substances available from garden shops produced especially for this purpose. Pruning is usu普立万(polyone)与农用薄膜制造商合作ally without interference from the leaves and also it is very unlikely that the cuts yu make will bleed. If this does happen,it is, of course,impossible to paint them properly.
uning should be done to ______.
ke the tree grow taller
prove the shape of the tree
t rid of the small branches
ke the small branches thicker
ees become unhealthy if the gardener ______.
lows too many branches to grow in the middle
es not protect them from wind
rces them to grow too quickly
mages some of the small side branches
y is a special substance painted on the tree?
make a wound smooth
prevent disease entering a wound
cover a rough surface
help a wound to dry
4.A good gardener prunes a tree______.
intervals throughout the year
quickly as possible
casionally when necessary
gular every winter
at was the author's purpose when writing this passage?
give pratical instruction for pruning a tree.
give a general description of pruning
explain how trees develop diseases
discuss different methods of pruning.
On Thursday afternoon Mrs. Carke, dressed for going out, took her handbag with her money and her key in it, pulled the door behind her to lock it and went to the over 60s Club. She always went there on Thursdays. It was a nice outing for an old woman who lived alone.
At six o'clock she cane home, let herself in and at once smelt cigarette smoke. Cigarette smoke in her house? How? How? Had someone got in? She checked the back door and the windows. All were locked or fastened, as usual. There was no sign of forced entry.
Over a cup of tea she wondered whether someone might have a key that fitted her front door-"a master key"perhaps. So she stayed at home the following Thursday. Nothing happened. Was anyone watching her movements? On the Thursday after that she went out at her usual time,dressed as usual, but she didn't go to the club. Instead she took a short cut home again, letting herself in through her garden and the back door. She settled down to wait.
It was just after fou扭转缠绕一体试验机