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Thanks to modern technologies, we now have the solutions to most eyesight problems. Doctors can use different treatments—PRK, Lasik (镭射视力矫正术) , Lasek and Intraocular
Lenses—to solve all types of eyesight problems while limiting the side effects. People believe eye operations are about as safe and effective as surgery (外科手术) can be. However, for an industry that promises clearness, many hospitals have kept their patients in the dark about the risks and realities. Governments are of no help either as there are no limits to who can buy medical instruments.
Despite a good record of the surgery, thousands of people around the world suffer from an eye operation that goes wrong. The consumer - advocate website surgicaleyes.com posts an astonishing series of unhappy endings—infected corneas(角膜),triple vision (三重视觉) and permanently damaged eyesight. The message boards are full of people who came out of Lasik with far better vision but still in great unhappiness, affected by poor night vision, dry eyes and worse. It's vital to research the subject if you're considering surgery. Here's a guide to help you see things clearly.
Know what you're getting into. If you believe all the ads, after eye surgery, you'll be able to read the bottom line of an eye chart through a brick wall. If only it were true. You may not end up with a vision as good as is promised. Besides, eye surgery still isn't fit for people with certain severe vision problems or an eye disease. The same goes for children under 18 and pregnant women, whose eyes may be experiencing changes. So don't be shocked if a doctor gazes into your eyes and shows you the door. Finally, be prepared for side effect. Some complain of dry eyes and require eye drops known as artificial tears for months. Others see light circles and star bursts while driving at night. Fortunately such symptoms tend to be minor and fade away.
Find a doctor. Ask friends for recommendations or look for one on the Internet. Whatever you do, don't make a decision on a rock - bottom price. You have only one set of eyes.
Ask tile doctor right questions: Who will be doing the operation? Being easily available and open communication with the doctor and his team are typical features of a good practice. What are your qualification certificates'? How much experience do you have? What's your complication rate(并发症比率)? The best doctors have a serious surgical complication rate below 1 percent. Beware of doctors who can't answer these questions. Finally, what's included in the price? Watch out for hospitals that offer a low price and then charge for extras for later visits.
50. From the first paragraph we know that____________.
A. doctors can deal with any eyesight problem without side effects
B. people are still concerned about the safety and effect of eye surgery
C. some hospitals don't tell the patients all the truth about eye surgery
D. government now do not care who can buy medical instruments
51. The writer mentions some information from a website to show that ___________.
A. the risk of having eye surgery is higher than expected
B. more and more people begin to take eyesight surgery
C. eyesight surgery can not bring people true happiness
D. much information about eye surgery on the Internet is false
52. By using the underlined words "shows you the door", the writer means the doctor ________.
A. shows you how to get to the operating room
B. will not carry out an eyesight operation on you
C. examines your eyesight with an eye chart on the door
D. asks you to open the door and let the next patient in
53. In the writer's opinion, what attitude should people hold before eyesight surgery?
A. Supportive. B. Doubtful. C. Cautious. D. Casual.
54. According to the passage, what kind of doctor is preferable for eye surgery?
A. A doctor who offers a low price
B. A doctor with a high complication rate.
C. A doctor willing to communicate with patients
D. A doctor working in a large hospital
D
Florida farmer Lohfner doesn't like moths(蛾). "They eat my vegetables," he complains. But
Lohfner has a secret weapon in his fight against moths: pheromones (外激素). Lohfner uses traps that release a female moth pheromone that is very attractive to male moths. Lohfner says that his traps catch almost 100 moths a week. For these moths, following pheromones cause their death. Nevertheless, for other moths and many insects, life would not be possible without pheromones.
For moths, pheromones are a matter of life and death. Moths have poor vision, and most cannot use sound to communicate, As a result, most moths depend on pheromones to send messages. Female moths release pheromones from their legs and wings. These pheromones can stay in the air for hours. A male moth can identify female moth pheromones from as many as five miles away.
Like moths, ants use pheromones to find each other; they also use pheromones to find their
homes and food. When an ant finds food, it takes a piece and heads toward home. Along the way, it releases a trail of pheromones. Other ants follow the trail to find the food. If the trail becomes
blocked, the ants look for a new way to reach the food. When they find then shortest way, they
create a new trail of pheromones. In this way, pheromones help ants adapt to changes in their
environment.
Ants even have different pheromones for different purposes. When an ant is hurt, it produces an "alarm" pheromone. Other ants identify the alarm pheromone and immediately come to help the hurt ant. The more serious the alarm, the more pheromones the ant produces. In this way, ant can quickly organize when they are in danger. Large groups of ants will form to fight insects hundreds of times their size. Some species of ants even use "trick" pheromones. Fire ants, for example, use trick pheromones to attack the homes of other ants. The trick pheromones confuse other ants and cause them to attack each other.
Some insects, remarkably, can use trick pheromones to imitate other species. This can help
them to find a meal, or in the case of the Mountain Alcon Blue butterfly, to avoid becoming the
meal. During its caterpillar (幼虫) stage, this unusual insect releases a pheromone similar to that of an ant. If the ants find a Mountain Alcon Blue butterfly caterpillar in the forest, they carry it home. There, instead of eating it, they care for it as if it were a family member. The caterpillar is given a private room and lots of food. If attacked, the mistaken ants will give their lives to protect the caterpillar, just as they would for their offspring.
Another creature has even learned how to use pheromones in the same way as farmer Henry
Lohfner to catch moths. The bolas spider, a species common in South America and Africa, produces a pheromone similar to that of a female moth. It waits in trees for a male moth to arrive. Hoping to find a female, the moth becomes a meal for the spider instead.
To sum up, pheromones are involved in every part of the insect life, from communication to finding food and protecting the home. Many biologists say pheromones are the true language of insects. And now, it is a language biologists are starting to understand.
55. The method the writer uses to introduce the topic is___________.
A. offering analyses B. providing explanations
C. giving examples D. making comparisons
56. Which of the following statements is true according to the passage?
A. Only female moths release pheromones.
B. Moths need pheromones to communicate
C. Male moths cannot identify pheromones from far away
D. For male moths, following female pheromones causes their death.
57. Which of the following statements best summarizes Paragraph 4?
A. Ants also have trick and alarm pheromones.
B. Ants are not afraid to fight other species because of pheromones
C. Ants are able to confuse other ants with pheromones
D. Ants use pheromones to find caterpillars
58. What does the underlined word "it" in Paragraph 6 refer to?
A. The ant B. The spider. C. The moth D. The butterfly
59. A Bolas spider in Paragraph 6 uses pheromones ___________.
A. to find mates B. to find food C. to trick others D. to send an alarm message
60. Which of the following is the best title for the passage?
A. The Research of Pheromones B. The Kinds of Pheromones
C. The Science of Pheromones D. The Language of Pheromones
