Your cell phone holds secrets about you. Besides the names and numbers that you’ve programmed into it, traces of your DNA remain on it, according to a new study.
DNA is genetic material that appears in every cell. Like your fingerprint, your DNA is unique to you --- unless you have an identical twin. Scientists today usually analyze DNA in blood, saliva(唾液), or hair left behind at the scene of a crime. The results often help detectives identify criminals and their victims.
Meghan J. McFadden, a biologist at McMaster University in Hamilton, Ontario, heard about a crime in which the suspect bled onto a cell phone and later dropped the device. This made her wonder whether traces of DNA remained on cell phones --- even when no blood was involved. To find out, she and a colleague collected flip-style(翻盖式) phones from 10 volunteers. They collected invisible traces of the users from two parts of the phone: the outside, where the user holds it, and the speaker, which is placed at the user’s ear.
The scientists scrubbed(meaning “cleaned”) the phones using a liquid mixture made mostly of alcohol. The aim of washing was to remove all detectable traces of DNA. The owners got their phones back for another week. Then the researchers collected the phones and repeated collecting traces on each phone once more. They discovered DNA that belonged to the phone’s owner on each of the phones.
Surprisingly, DNA showed up even in swabs that were taken immediately after the phones were cleaned. That suggests that washing won’t remove all traces of evidence from a criminal’s cell phone. So cell phones can now be added to the list of clues that can help a crime-scene investigation.
【小题1】McFadden decided to find out whether people leave their DNA on their cell phones when she ____ .
| A.got her cell phone lost by chance |
| B.found a cell phone with blood on it |
| C.heard about a crime involving a cell phone |
| D.did research on cell phones |
| A.let them leave their traces on their phones |
| B.avoid keeping their cell phones too long |
| C.give them a chance to get rid of their secrets |
| D.find out who is responsible for the crime |
| A.do harm to people | B.should be often cleaned |
| C.disclose people’s secrets | D.help deal with crimes |
| A.The reason for collecting the phones from volunteers. |
| B.The technique of collecting DNA on the phones. |
| C.The method of removing traces of DNA on the phones. |
| D.The purpose of washing the cell phones. |
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There are many international organizations which work to save and protect endangered species(物种)and natural environment.If you would like more information about any of the organizations listed below, you can write to the addresses given.
| Friends of the Earth(FOE)campaigns on a range of problems including rainforests,the countryside,water and air pollution and energy· Friends of the Earth International Secretariat P.O.Box 19199 1000 G.D. Amsterdam The Netherlands | Greenpeace uses peaceful but direct action to defend the environment. It campaigns to protect rainforests and sea animals,stop global warming and end pollution of air,land and seas.It also opposes nuclear(核)power. Greenpeace International Keizergracht 176 1016 DW Amsterdam The Netherlands |
| BirdLife International is an organization which works to save endangered birds all over the world. BirdLife International Wellbrook Court Girton Road Cambridge CB3 ONA England | WWF-World Wide Fund For Nature is the world's largest private international organization for the protection of nature and endangered species. Information Officer WWF International Avenue du Mont-Blanc 1196 Gland Switzerland |
A.call them B.write them a letter C.visit them D.send them an e-mail
67.BirdLife International is an organization trying to .
A.reduce pollution B.defend rainforests
C.protect ocean animals D.save endangered birds
68.If you oppose nuclear power,you can join .
A.Friends of the Earth B.World Wide Fund For Nature
C.Greenpeace D.BirdLife International
69.What can we learn about WWF?
A.It helps to protect nature and save endangered animals.
B.It is the world’s largest international organization.
C.It works for private companies and rich people.
D.It is a private organization in the United States.
70.Which is the best title for the passage?
A.Environmental Protection Organizations B.Global Traffic Problems
C.Endangered Animals D.Natural Beauty
The ocean contains many strange and surprising creatures. One such creature is the puffer fish. This very strange fish is probably the most poisonous creature in the ocean. The poison that this fish produces is 275 times more poisonous than the chemical which is usually used to kill rats.
The puffer fish gets its name from the way the fish protects itself from enemies. Whenever it is attacked, the fish blows up its body to three times bigger than its normal size!
Another strange thing about this fish is the fact that it can swim like other fish. Because it does not have bones like oth
er fish, the puffer fish can only move slowly through the water as it is carried by waves.
The puffer fish also has funny teeth. These teeth stick out of the fish’s mouth and are used by the fish to open the shells of the creatures that live on the ocean floor.
This strange, ugly, and very poisonous fish is actually a very expensive kind of food in Japan. The Japanese call this fish “fugu”, and people have been known to pay $150 per person to eat a fugu meal (usually eight servings)!
Very brave people want to eat the most poisonous part of the fugu fish on purpose. They think that this part of the fish tastes the best! Strict laws have been passed to control restaurants which serve fugu; however, quite a few people have still died from eating fugu.Almost 200 people have died over the past 25 years.
When people eat fugu poison, they do not die on the spot. First, they feel a strange tickle on their lips and in their mouth. Then they can not feel anything with their fingers. Finally, they cannot move or speak. Death follows when they can no longer breathe. The poison may take only a few minutes or up to six hours to kill a person. There is no known cure for fugu poisoning.
【小题1】According to the passage, the puffer fish .
| A.is probably the most poisonous creature in the world |
| B.is generally considered to be the strangest fish in the ocean |
| C.is slightly more poisonous than the chemical used to kill rats |
| D.is without doubt a deadly creature if it is not eaten properly |
| A.It becomes bigger. | B.It has funny teeth. |
| C.It gives off poison. | D.It can swim swiftly. |
| A.now and then | B.once in a while |
| C.then and there | D.sooner or later |
| A.The Japanese government. | B.Licensed restaurants. |
| C.Strict lawyers in Japan . | D.Very brave people |
| A.Having difficulty breathing. | B.Having no sense of touch. |
| C.Having no sense of taste. | D.Having trouble speaking. |