Passage 8
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 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 trees to grow in their own ways.
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 causing wounds.The health of a tree may be encouraged by removing the 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 diseases,but it is a wound that will heal.Often there is a race between the healing and the disease as to whether the tree will live or die,or that there is a period when the tree is at risk.It should be the aim of every gardener to reduce the risk as far as possible.It is essential to make the area which has been pruned smooth and clean,for healing will be slowed down by roughness.You should allow the cut surface to dry for a few hours and then paint it with one of the substances available from garden shops produced especially for this purpose.Pruning is usually done in winter for then you can see the shape of the tree clearly without the interference（妨碍）from the leaves and it is,too,very unlikely that the cuts you make will bleed If this does happen,it is,of course,impossible to paint them properly.
Why should pruning be done?（ ）
从文章第二段可以看出，修剪树木有两个作用：1.确保树木的外形和大小；2.让树木更健康。A因为修剪能让树木长得更高；B因为修剪能改善树木形状；C因为修建能避免小树枝；D因为修剪能让小树枝长得繁茂。结合四个选项，只有B选项更恰当。故正确答案是选项B。
根据《中华人民共和国中国人民银行法》的规定，我国货币政策的最终目标是（ ），并以此促进经济增长。
箱子里面有红、白两种玻璃球，红球数比白球数的3倍多两个，每次从箱子里取出7个白球、15个红球。如果经过若干次以后，箱子里只剩下3个白球、53个红球，那么，箱子里原有红球比白球多多少个?
将自然数1~100分别写在完全相同的100张卡片上，然后打乱卡片，先后随机取出4张，问这4张先后取出的卡片上的数字呈增序的几率是多少？（）
对于债券利率的风险结构，描述正确的有（ ）。
市场经济体制下，财政具有的职能有( )。
（ ）决定着生产关系。
左边给定的是纸盒的外表面，下列哪一项能由它折叠而成？（ ）
货币制度最基本的内容是规定（ ）。
如果一国货币汇率上升，即对外升值，就可能会导致（ ）。
（）
