题目内容
Properly _______ with numbers, the books can be easily found.
A. marked B. mark C. to mark D. marking
A
暑假作业暑假快乐练西安出版社系列答案Food sometimes gets poisoned with harmful things. A person who eats such food can get an illness called food poisoning. Food poisoning is usually not serious, but some types are deadly. The symptoms of food poisoning usually begin within hours of eating the poisoned food. Fever is one of the most common symptoms.
Certain microorganisms（微生物）cause most types of food poisoning. Bacteria and other microorganisms can poison eggs, meat, vegetables, and many other foods. 
After entering the body, these tiny living things release（释放）poisons that make people sick.W_w w.k*s*5 u.c@o m
Some chemicals can also cause food poisoning. They are often added to food while it is being grown, processed, or prepared. For example, many farmers spray chemicals on crops to kill weeds and insects. Some people may have a bad reaction to those chemicals when they eat the crops.
Some plants and animals contain natural poisons that are harmful to people. These include certain kinds of seafood, grains, nuts, seeds, beans, and mushrooms.W_w w.k*s*5 u.c@o m
When people handle food properly, the risk of food poisoning is very small. Microorganisms multiply rapidly in dirty places and in warm temperatures. This means that people should never touch food with dirty hands or put food on unwashed surfaces. Food should be kept in a refrigerator to stop microorganisms from growing. Meat needs to be cooked thoroughly to kill any dangerous microorganisms. People should also wash food covered with chemicals before eating it. Finally, people should not eat wild mushrooms or other foods that grow in the wild. Some of these foods may contain natural materials that are poisonous to humans. In addition, some types of fish can be poisonous.
Most people recover from food poisoning after a few days of resting and drinking extra water. If people eat natural poisons, they must go to the hospital right away to have their stomachs emptied.
【小题1】Which of the following statements is NOT true?
| A．Food when poisoned can make people sick. |
| B．Food poisoning means death. |
| C．Food poisoning comes in varieties. |
| D．Food poisoning can be serious. |
| A．are always accompanied by a fever |
| B．are too common to be noted |
| C．can be noticed within hours |
| D．can he ignored |
| A．some chemicals |
| B．low temperatures |
| C．some tiny living things |
| D．certain natural materials |
| A．mushrooms should not be eaten |
| B．vegetables are safer than meat and seafood |
| C．natural poisons are more dangerous than chemicals |
| D．different types of food should be handled differently |
| A．natural materials are safe in food processing |
| B．chemicals are needed in food processing |
| C．food poisoning can be kept under control |
| D．food poisoning is out of control |
The air bag is a piece of safety equipment in cars. It was first designed by John W. Hetrick in 1952. Like many inventions, he came up with the idea as a result of an event that had occurred in his life. He says:
“In the spring of 1952, my wife, my seven-year-old daughter, Joan, and I were out for a Sunday drive in our 1948 Chrysler Windsor. About three miles outside Newport we were watching for deer jumping across the road. Suddenly, there was a large rock in our path. I hit the brakes and we went into a ditch(壕沟).
“As I applied the brakes, both my wife and I threw our hands up to keep our daughter from hitting the car. There was soft mud in the ditch, so the car wasn’t damaged, and no one was hurt.”
“During the ride home I couldn’t stop thinking about the accident. I asked myself,‘Why couldn’t some object come out to stop you from striking the inside of the car?’As soon as I got home that night I drew some sketches(草图). Each evening for the following two weeks, I’d add or reduce something from the sketches.”
Hetrick applied an event he had observed while in the Navy to the design of the air bag. He was repairing a torpedo(鱼雷) which had a cloth covering. When the compressed（压缩的） air that was in the torpedo was let out, the covering was suddenly filled with air and was shot to the ceiling.
With this knowledge, he developed his design until he was able to obtain a patent on the invention on August 5, 1952. The idea was similar to the air bag designs of today. Compressed air is stored in a container and when a traffic accident occurs and the car slows down at a rapid enough rate, the air will be released into the air bag. The idea was ingenious, but Hetrick’s air bag never would have functioned properly. It was really a breakthrough, but it would require years and years of designing and testing by some top car designers before it could be used.
【小题1】The car accident Hetrick was involved in ________.
| A．damaged his car | B．happened in 1948 |
| C．was caused by a deer | D．caused no harm to his family |
| A．turned out to be dangerous | B．was helpful to his invention |
| C．involved designing torpedoes | D．inspired him to design an air bag |
| A．creative | B．ridiculous | C．crazy | D．complex |
| A．It came into use in the 1950s. | B．It performed perfectly in car accidents. |
| C．It prepared the way for air bags nowadays. | D．It took Hetrick about two months to develop it. |
| A．the great inventor Hetrick | B．The invention of air bags |
| C．a terrible car accident | D．road safety in the 1950s |