6.26. Fill in the gaps choosing one of the words in brackets
Plastics
Plastics are usually produced by synthesis from such natural materials as water, air, salt, coal, and natural gas. The technology is simple and cheap. While (1) _____ (solid, cheap, uniform) in finished state, plastics are liquid at some stage of manufacture, and it is easy to form plastics into various shapes. Plastics are different in (2) _____ (hardness, properties, needs), characteristics and (3) _____ (pressure, application, thermosets). Plastics are (4) _____ (reliable, available, thermoplastics), (5) _____ (expensive, cheap, structural), durable. Plastics resist (6) _____ (weight, strength, corrosion). Plastics are machined like (7) _____ (metals, ceramics, carbon).
Their (8) _____ (lightness, high weight, colour), strength, hardness, chemical resistance, (9) _____ (colour, durability, application) make it possible to use plastics in electric and electronic equipment, transportation, agriculture, etc.
The application of plastics is (10) _____ (achieving, satisfying, calling for) the requirements of all industries. There is no industry now where plastics are not used.
6.27. Answer the following questions:
1. What materials are usually used to build bridges?
2. What properties are important for such materials?
6.28. Listen to the text ‘Experimental Bridge’ and complete your answers if there is any new information in the text. Why is the bridge experimental?
6.29. Listen again. What do the following numbers refer to?
32 ft; 80 ft; 10 ft; 4 ft; 2 months; 12,000 lb; 9,000 lb
6.30. Answer the following questions:
What are the advantages and disadvantages of this experimental bridge?
Do you think the material used for constructing it could be used for this purpose?
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