题目内容
Is the gas ________ somewhere?
- A.escapes
- B.escaped
- C.escaping
- D.escape
考查escape的用法
escape意为“漏出”时为不及物动词，故没有被动的形式。故答案是C。
备战中考寒假系列答案What does fizz (气泡) taste like? In Bubbly (多泡的)drinks such 
as sodas, tiny bubbles give the drink a lift--- and have a distinct taste, In a new study on mice, scientists have connected that fizzy-taste feeling to the ability to taste sourness, such as that of oranges or vinegar.
Scientists first thought the taste of bubbles came from the bubbles bursting on the tongue, but now ate starting to think differently. Charles Zuker, of Columbia University, and his team studied the nervous system of mice to understand how the tongue tastes carbon dioxide, which is the gas that makes up the bubbles.
Animals, including human beings, are able to detect different tastes by using taste buds(味蕾) which pick up tastes in the mouth, and then send them to the brain. In the experiment, different groups of mice were genetically engineered to be missing one of the senses involved in taste. “Genetically engineered” means the researchers were able to turn off the switches for certain senses by changing the genes responsible for taste. The mice in one group could not taste sweet; another, sour; the third, bitter, and the fourth, salt. When the scientists gave carbon dioxide to the mice, the nervous systems of all the mice responded to the gas, except those of the mice that could not taste sour.
This shows that the taste of the bubbles must be sour, and that by turning off the ability of the mice to taste sour, the scientists also turned off their ability to taste carbon dioxide. When they studied the cells that detect sourness, the researchers found a protein attached to the cells that is important to the process of tasting carbon dioxide. When carbon dioxide comes into contact with this protein, the protein knocks off particles called protons. These protons(质子), in turn, travel to the brain, which says ,” Hey! That’s a taste!”
It may seem like a lot of work to get from a can of soda to a taste, but the science of the senses is anything but simple, “ Taste is a challenging system to study,” one researcher says.
【小题1】 What is the most important function of the bubbles?
| A．To look interesting . | B．To make drinks taste good. |
| C．To make drinks funny. | D．To produce a lot of fizz. |
| A．sourness has nothing to do with the taste of bubbles. |
| B．there is a connection between sourness and bubbles. |
| C．the taste of bubbles is better if it’s less sour. |
| D．most mice cannot taste carbon dioxide. |
| A．the taste of bubbles is produced by the bubbles bursting on the tongue. |
| B．the nervous systems of mice show how the tongue tastes carbon dioxide. |
| C．taste seems simple but is very complex to research. |
| D．nerve cells sending signals to the brain is the first step in tasting something. |
| A．Nervous Systems Understand How the Tongue Tastes. |
| B．The Process of Taste |
C．The taste of Bubbles. |
| D．Different Animals Detect Different Tastes. |
People and the sources of air pollution are found in the same places. This means that cities with large populations have the biggest problem of dirty air. Air pollution is caused by many different things. A major source of air pollution is the gas fumes from cars. Statistics show that 93 percent of all auto trips are within cities. Another major source of dirty air is the burning of coal and oil for energy. This energy is needed to make electricity. Of course, much more electricity is used in the city than in the country.
On the average, we throw away more trash and garbage than the year before. The burning of garbage contributes to air pollution. Many major industries are also responsible for the dirty air in the around cities. The fumes from iron, steel, chemical, and petroleum production add particles to the air.
The effects of air pollution range from mild headaches to death. The levels of pollution found in heavy for traffic may cause headaches for loss of clear vision. Wherever coal and oil are used for fuel, fumes may kill trees and plants and cause metal to corrode. In some of the larger cities, these fumes endanger the live of human beings by contributing to lung diseases and causing early death.
【小题1】The key point of the passage is that _________.
| A．the cause of air pollution is people |
| B．the causes and the effects of air pollution are both found in cities |
| C．the effects of air pollution range from headaches to death |
| D．air pollution is caused by dirty air |
| A．to persuade people to stop polluting the air |
| B．to tell the causes of air pollution |
| C．to tell why cities are bad places to live |
| D．to describe why cities are bad places to live |
| A．Because there are larger populations in cities. |
| B．Because the air in the city is dirty. |
| C．Because there are more cars in the city. |
| D．Because there are much more gas fumes from cars and burning of coal and oil for energy in the city than in the country. |
| A．to corrode | B．to twist |
| C．to turn black | D．to become rusty |
| A．heart disease | B．loss of clear vision |
| C．lung diseases | D．serious headache |