III．Reading Comprehension
Section A
Directions: For each blank in the following passage there are four words or phrases marked A, B, C and D. Fill in each blank with the word or phrase that fits the context.
A detailed study of biological diversity（多样性）in town and city gardens has found that they offer a vital refuge for animals and plants. It has also fund that many of the ideas about wildlife gardening are not 50 .In fact, small gardens are just as good as big gardens at 51 wildlife, suburban gardens are not always better than city gardens and non-native plants are not always harmful to native insects and birds. Britain’s 16,000,000 gardens are a refuge for hundreds of species of animals and plants that would find it 52 to survive onintensively （精细地）farmed land. According to the study, gardens are amazingly varied even compared to 53 environments that are good for wildlife. Small gardens are more interesting 54 they vary a great deal in botanical environment, All the wildlife responds to the variation.
Ken Thompson of Sheffield University was involved n the first detailed study of the 55 living in British gardens when he and his colleagues surveyed 61 gardens in Sheffield. They really found a(n) 56 diversity of plants and animals. They also identified a range of simple 57 that improved a garden’s environment for wildlife. The top thing is to grow more big trees as these greatly 58 the volume of vegetation in the garden and a lot of 59 means a lot of places to live and a lot of things to eat. 60 , create a pond for insects and frogs. Think before stocking it with fish which will eat insect eggs. Also, it is not wise to light up the garden at night with bright lawn lamps, which will 61 many night creatures, Finally, don’t be too tidy: don’t be 62 to clear up everything when the garden stops flowering. Just 63 a bit of things lying around.
To sum up, people who want to turn their gardens into wildlife refuges should 64 and let the grass grow tall, the flowers turn to seed and trees expand skyward.
50．A．true B．basic C．vivid D．simple
51．A．selecting B．importing C．offering D．attracting
52．A．impossible B．illegal C．lucky D．convenient
53．A．peaceful B．warm C．natural D．clean
54．A．before B．unless C．but D．because
55．A．wildlife B．men C．germ D．pet
56．A．confusing B．complete C．surprising D．orderly
57．A．measures B．standards C．services D．functions
58．A．occupy B．increase C．limit D．reduce
59．A．vegetation B．reservation C．preparation D．decoration
60．A．By contrast B．As a result C．In other words D．In addition
61．A．block B．disturb C．benefit D．protect
62．A．in a mess B．in a way C．in a hurry D．in a while
63．A．forget B．remove C．avoid D．leave
64．A．escape B．relax C．strive D．retire
多次从斜轨上同一位置静止释放，找到其平均落地点的位置B，测量平抛射程
。然后把被碰小球
静止于轨道的水平部分，再将入射小球
相碰后平均落地点的位置A、C
，
，小球落地点的平均位置到Ｏ点的距离如图所示。碰撞前、后
与
，则
：11；若碰撞结束时
，则
=11: ；所以，碰撞前、后总动量的比值
= ；实验结果说明 .
……………………（2分）
；………（每空1分）
，球a和球b碰撞后抛出的速度分别为
，
则我们要验证动量守恒即：
，测速度是关键，平抛运动的初速度
即
，因为平抛运动的高度一定，所以
，即