2.17. Translate into English.

1. Дефекты древесины влияют на ее прочность.

2. Качество древесины, используемой для крепей, зависит от влияния влаги и времени года.

3. Причинами разрушения деревянной крепи являются гниль, пожар, обрушение и др.

4. Существуют способы продления срока службы деревянной крепи.

2.18. Translate in writing 1 and 2 from the text given above.

Unit 3.

3.1. Read and memorize the words.

blast	n	взрывать
commercial	a	промышленный
explosive	n	взрывчатка, ВВ
dam	n	дамба
groove	n	канавка
spill	n	просыпание, просачивание; просыпаться, просачиваться
quarry	n	карьер

3.2. Recognize the international words and word combinations.

dynamite, cascade tunnel, start, ton, primitive method, section, modern method, aqueduct, concentrated energy

3.3. Translate the derivatives.

blast – blasting; explode – explosion – explosive; start – started – starting; use – user – used – using; require – required – requirement; convey – conveyor

3.4. Define functions of ing-forms. Find in the text “Explosives. Historical Note” sentences with ing-forms and translate them.

3.5. Find in the same text sentences with the Infinitive and translate them.

3.6. Read the text and answer the questions under it.

Explosives. Historical Note

Many of great engineering feats of the world were accomplished at a time when the use of explosives for blasting was unknown. During the building of King Solomon’s temple, which was begun in 983 B.C., some 80,000 men laboured in subterranean quarries breaking out blocks of stone with wooden wedges driven into grooves in the rock and then wet with water. King Hiram of Tyre, a contemporary of king Solomon, is thought to have secured 3 tons of silver per year from the Rio Tinto mine through the efforts of 40,000 men. The Roman Emperor Claudius, in the first century A.D., completed the aqueduct started by Caligula to convey water to Rome from Lake Fucinus some 50 miles distant. To drive a tunnel 6 by 10 ft in section and 3, 5 miles long under Monte Salviano required the work of 30,000 labourers for 11 years, using the primitive method of breaking the rock by wooden wedges and also by fire setting. It would take 100 men about 10 months to drive such a tunnel using modern methods and explosives. Even the great Rajasamand Dam in the Aravelli Mountains of the Indian kingdom of Rajputana, begun in 1661, required 20 years for building. Made of white marble, the dam is 40 ft high at the spillway, and it impounds a lake 30 miles in circumference. Dynamite did not come into use until 1867, but through the aid of dynamite and other high explosives it has been possible to take from I mine over 2, 5 million tons of ore a year, to drive the Cascade tunnel at the rate of 55 ft per day, and to blast from a quarry over 2 million tons of rock at one shot. Nuclear explosives, although unproven commercially (1963), contain tremendous amounts of concentrated energy for possible use in large-scale blasting operations.