10. Чтение: понимание основного содержания текста: #253163

Установите соответствие между текстами A–G и заголовками 1–8. Используйте каждую цифру только один раз. В задании один заголовок лишний.

1. Figuratively speaking
2. Silver versus gold
3. Key facts
4. Precious doctor
5. Useful in many ways
6. The history of silver
7. Silver symbols
8. Potentially dangerous

A. Silver is a chemical element with the symbol Ag (from the Latin ‘argentum’, meaning ‘shiny’). Its atomic number is 47. Silver is a soft, white metal which exhibits the highest electrical conductivity, thermal conductivity and reflectivity of any metal. Silver is found in the Earth’s crust in a pure, free elemental form (the so-called ‘native silver’) together with gold and other metals, and in some minerals. Most silver is produced as a byproduct of copper, gold, or zinc refining.

B. Other than in currency and as an investment medium, silver is used in solar panels, water filtration, jewelry and silverware making, in electrical contacts and conductors, mirrors and so on. You may not know this, but silver is also necessary for window coatings, in the catalysis of chemical reactions, and even as a colorant in stained glass and in specialized confectionery. Its compounds are also used in photographic and X-ray film and making bandages and wound dressings.

C. In medicine, silver is incorporated into wound dressings and used as an antibiotic coating in medical devices. Wound dressings containing silver are used to treat external infections. Silver is also used in some medical applications, such as catheters and breathing tubes. This is because the silver ion is bioactive and in sufficient concentrations it successfully kills harmful bacteria. Silver compounds are easily taken into the body like mercury, but lack the toxicity of the latter.

D. Silver compounds have low toxicity compared to those of most other heavy metals as they are poorly absorbed by the human body. However, some silver compounds are caustic and can cause stomach and breathing disorders. Animals repeatedly dosed with silver salts have been observed to experience slowed growth and liver and kidney problems. Colloidal silver causes poisoning. Some waterborne species are particularly sensitive to silver salts and those of other precious metals.

E. Silver plays a certain role in mythology and has been used in folklore. Greek poets often used silver to denote somebody or something which is second best. In folklore, silver was commonly thought to have mystical powers. For example, a silver bullet in folk tales is supposed to be the only effective weapon against monsters. In many books, however, silver also represents greed and degradation of consciousness; this is the negative aspect, the unfair treatment of its value.

F. Silver was one of the seven metals that were known to prehistoric humans and whose discovery is thus lost to history. In particular, three metals – copper, silver, and gold – occur in elemental form in nature and were probably used as the first primitive forms of money, as opposed to simple bartering. Since silver is more reactive than gold, supplies of native silver were much more limited than those of gold. For example, silver was more expensive than gold in Egypt.

G. The English language has a lot of phrases and idioms with the word ‘silver’. If a person is very lucky, they say that this person was born with ‘a silver spoon in their mouth’. If you want to encourage somebody who has problems, you may say that ‘every cloud has a silver lining’ and eventually things will turn out fine. You say that ‘speech is silver, but silence is golden’ when you are not happy with somebody’s words. It is certainly interesting to learn about such expressions.