Most of us【B1】______taking certain things for granted. We tend to assume that experts and【
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Let us consider what science and technology have to contribute to the food problem.
The simplest way to increase food production, one might suppose, is to bring more land【B1】cultivation and put more people to work on it. Some of the underdeveloped countries have resorted to this【B2】approach, without notable success. It contains several fallacies. For one thing, it usually means【B3】into marginal lands where the soil and climatic conditions give a poor【B4】. Cultivation may quickly deplete this soil,【B5】it for pasture or forest growth. It is often possible, of course, to turn such lands into useful farms by agricultural【B6】; for instance, a sophisticated knowledge of how to use the available water【B7】an irrigation system may reclaim semi-arid grasslands for crop-growing. But the cultivation of marginal lands is in any case unsuccessful【B8】it is carried out by farmers with a centuries-old tradition of experience or by modern experts with a detailed knowledge of the【B94】conditions and the varieties of crops that are suitable for those conditions. Such knowledge is【B10】absent in the underdeveloped countries.
【B11】, we know that highly developed countries have not increased the【B12】of acres under cultivation,【B13】on the contrary have【B14】their marginal lands and steadily reduced the proportion of the population engaged in fanning. Efficient fanning【B15】concentration on the most efficient lands, and it results in greater production with【B16】people. The problem of the underdeveloped countries, then is to increase the【B17】of their farms and farmers. This would allow them to industrialize and to feed their people more adequately. It is not easy to【B18】, however. The farmers are conservative and resistant to change【B19】their methods of cultivation. The underdeveloped countries are greatly in need of studies and experiments to help them to【B20】modern agricultural methods to their own conditions.
【B1】
A.under
B.of
C.by
D.in
At this part of the lake there occurs a deep bay or inlet(水湾, 小港), to save rounding which travelers usually strike straight【B1】from point to point, making what is called in voyageur parlance(俗话) a traverse(横渡).These traverses are subjects of【B2】anxiety, and【B3】of delay to travelers. Being sometimes of considerable extent,【B4】from four and five—and in such immense seas as lake Superior—to fourteen miles.
With boats, indeed, there is【B5】to fear,【B6】the inland craft of the fur traders can stand a heavy sea, and often ride out a pretty【B7】storm; but it is far otherwise with the bark canoes that are often used in【B8】. These frail craft can stand very little sea—their frames being made of thin flat slips of wood and sheets of bark, not【B9】than a quarter of an inch thick, which are sewed together with the fibrous roots of the pine【B10】by the natives, and rendered water-tight by【B11】of melted gum(树胶). Although light and【B12】,【B13】, and extremely useful in a country where portages are【B14】, they【B15】very tender usage; and when a traverse has to be made, the guides have always a grave【B16】with some of the most sagacious(有远见的) among the men, us to the probability of the wind rising or【B17】 consultations which are more or【B18】marked by【B19】and tediousness in proportion to the length of the traverse, the state of the weather, and the courage or【B20】of the guides.
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A.across
B.cross
C.crossing
D.crossed
Dear Sirs,
The order mentioned above was delivered to our warehouse 2 days after it arrived in Chicago 8th Jan. and we regret that we have to complain about the conditions in which we received it.
In our order we stipulated that we required four dozen of your men's suits pattern CS/7, and in your invoice, No. CP/78, you charged us for this quantity, but it is clear that you have packed only three dozen in Case 3, 【B1】______ . We would therefore appreciate an explanation and your prompt action to send us the missing dozen suits.
Very much more serious is the condition of the ladies' trousers suits that you packed in Case 2. Of the six dozen that this case contains, 【B2】______ . It is quite clear that this is solely due to the totally inadequate way in which they had been packed for you had not lined the case with any waterproof paper. 【B3】______
【B4】______ , whereas in our order we had stated that we required your pattern CS/9 which is stated in your catalogue as being made up from heavy-weight material. There is no market here for tropical suits, and so we must emphasize 【B5】______ .
We must stress that the mistakes that you have made in this first order we have placed with you have caused considerable problems for us. We had hoped to include your products in the Spring Sale that is due to open at the end of February, but as it is, it is now clear that we shall not be able to do so. We wish to stress, therefore, that unless you take immediate action to correct the mistakes that you have made, 【B6】______ .
We now expect your prompt reply.
Yours,
Faithfully
A. please correct all the mistakes as soon as possible
B. that we expect you to replace these suits that have been wrongly delivered with those we ordered without delay
C. we shall certainly not consider further orders with you and shall report your company to the American Trade Promotion Office in New York
D. and we think the price is a little bit too high
E. forty have become very sodden in transit and most of these show signs of rotting
F. we are also surprised that you appear to have sent us three dozen lightweight gentlemen's suits in Case 1
G. we therefore expect your prompt action to remedy this situation
H. and there is no sign of the missing dozen in either Case 1 or 2
【B1】______
Most of us are blind to this interconnectedness of everything in the natural world.()
______ of the two suspects is arrested as most of us have expected.
A.Both
B.Neither
C.None
D.Either
Although it may sound funny to call scientists weather-watchers, there's【B3】funny about what they do. Specifically, weather-watchers are meteorologists(气象学者)【B4】work for the United States Weather Bureau. They study the ocean of【B5】that surrounds the earth and, with the information they get, predict our weather.
The atmosphere【B6】in height from 300 to 700 miles above the earth and is divided into a series of layers or shells. The layer that is most interesting【B7】the meteorologist is the troposphere(对流层) or the layer closest to the earth.【B8】is in the troposphere that all our weather is formed.
【B9】causes our weather is really a very simple process. Endless streams of hot air push up from the earth. As they rise, they are【B10】by the freezing temperatures of the【B11】troposphere. Once it has become cold and heavy, the air【B12】back toward the earth, but it【B13】move down because of the rising hot air. In the meantime, planetary winds, which blow around the earth, or air currents keep both the cold air mass as well as the hot air mass in【B14】.
There are two additional factors that influence these moving air masses.【B15】is water vapor that the rising hot air soaks up like a sponge. The other is temperature Which, by cooling the hot air, forces it to【B16】out its water vapor in the form. of rain, snow, or sleet(雨夹雪).
These air masses【B17】push against each other with tremendous pressure. When a high-pressure mass of air succeeds【B18】pushing out a low-pressure air mass, we have clearing conditions and【B19】weather. When a low-pressure air mass forces out a high-pressure mass of air, stormy weather can be【B20】.
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A.when
B.as
C.while
D.if