在拥挤的水域或大雾中，船舶使用汽笛，就像警车和救护车使用警报器一样。

There is something wrong with my TV set. I must have it______.

—My room gets very cold at night.—______.

New difficulties kept______as they built the railway tunnel.

理论上说，你的计划听上去不错，但实际上行得通吗?

（英语类学生必做）As the fatalities continue to occur daily in every state, some Americans are even beginning to think well of the 13 years of national prohibition of alcohol that began in 1919, which President Hoover called the "noble experiment". (Passage 4)

[此试题无题干]

Ask three people to look out of the same window at a busy street corner and tell you what they see. Chances are you will receive three different answers. Each person sees the same【C1】______, but each perceives【C2】______different about it. Perceiving goes【C3】______in our minds.【C4】______the three people who look out of the window,【C5】______may say that he sees a policeman giving a motorist a【C6】______Another may say that he sees a【C7】______traffic jam at the【C8】______. The third may tell you that he sees a woman trying to【C9】______the street with four children【C10】______tow. For perception is the【C11】______interpretation of what the【C12】______—in this case our eyes—tell us. Many psychologists today are working to try to【C13】______just how a person【C14】______or perceives the world around him. Using a scientific【C15】______these psychologists【C16】______experiments in which they can control all of the【C17】______By measuring and charting the【C18】______of many experiments, they are trying to【C19】______what makes different people perceive totally different things【C20】______the same scene.

Public goods are those commodities from whose enjoyment nobody can be effectively excluded. Everybody is free to enjoy the benefits of these commodities, and one person's utilization does not reduce the possibilities of anybody else' s enjoying the same good. Examples of public goods are not as rare as one might expect. A flood control dam is a public goods. Once the dam is built, all persons living in the area will benefit—irrespective of their own contribution to the construction cost of the dam. The same holds true for highway signs or aids to navigation. Once a lighthouse is built, no ship of any nationality can be effectively excluded from the utilization of the lighthouse for navigational purposes. National defense is another example. Even a person who voted against military expenditures or did not pay any taxes will benefit from the protection afforded. It is no easy task to determine the social costs and social benefits associated with public goods. There is no practicable way of charging drivers for looking at highway signs, sailors for watching a lighthouse, and citizens for the security provided to them through national defense. Because the market does not provide the necessary signals, economic analysis has to be substituted for the impersonal judgement of the marketplace.

Scientists will have to______ new methods of increasing the world' s food supply.

Maggie had a wonderful time at the party? —______, and so did I.

Looking back on my childhood, I am convinced that naturalists are born and not made. Although we were all brought up in the same way, my brothers and sisters soon abandoned their pressed flowers and insects. Unlike them, I had no ear for music and languages. I was not an early reader and I could not do mental arithmetic. Before World War I we spent our summer holidays in Hungary. I have only the dim memory of the house we lived in, of my room and my toys. Nor do I recall clearly the large family of grand-parents, aunts, uncles and cousins who gathered next door. But I do have a crystal-clear memory of the dogs, the farm animals, the local birds and, above all, the insects. I am a naturalist, not a scientist. I have a strong love of the natural world, and my enthusiasm has led me into varied investigations. I love discussing my favorite topics and enjoy burning the midnight oil while reading about other people's observations and discoveries. Then something happens that brings these observations together in my conscious mind. Suddenly you fancy you see the answer to the riddle, because it all seems to fit together. This has resulted in my publishing 300 papers and books, which some might honor with the title of scientific research. But curiosity, a keen eye, a good memory and enjoyment of the animal and plant world do not make a scientist; one of the outstanding and essential qualities required is self-discipline, a quality I lack. A scientist requires not only self-discipline but hard training, determination and a goal. A scientist, up to a point, can be made. A naturalist is born. If you can combine the two, you get the best of both worlds.

Every summer she______the neighbors at an outdoor party.

We need not wish for what we don't have, but enjoy what we do possess today.

Despite the rescuers' strenuous efforts, hopes of finding the missing climbers are now beginning to______.

Oh, ______I could speak several languages now!

If the police A would have B arrived earlier, he C would have D seen the accident.

We' d better start early. We don' t want to risk ______ in the traffic.

The number of private colleges______.

However difficult it may be, I will never lose my confidence.