【单选题】

Plastic is the panacea of the ages. Nearly every man-made object (1) (2) of, or at least (3) its very structure, to this wonder compounD、Rain slickers, computer terminals, automobile engine parts, coffee cups (and the sugar stirrers too), breast implants, toy soldiers--they are all made up of plastic, or one of its many (4) . Since the (5) of civilization, humankind has been experimenting (6) a multifunctional material--one that had to be equally strong and lightweight--to carry, contain and protect valuables. (7) it could carry, contain and protect humans too, evenBetter. Generations of tinkerers and scientists set off (8) the challenge, striking gold some 170 years ago.By mixing natural rubber with sulphur they created the world’s most utilized material ever. In developing a (9) , malleable and durable substance, the most important inventions of the industrial age were to follow shortly thereafter. The automobile and airplane industries, to (10) just two, owe their very existence to plastiC、And, (11) celluloid plastic strips, the LumiereBrothers would never have brought moving pictures to the big screen.

The development of plastic is a story of human (12) , ingenuity and luck. (13) the legend now goes, in 1839, theAmerican inventorCharles Goodyear (the famous tyre company would later use his name) was experimenting with the sulphur treatment of natural rubber when he dropped a piece of sulphur treated rubber on a stove; The heat seemed to give rubber (14) properties. It was stronger, more (15) to abrasion, more elastic, much less (16) to temperature, (17) to gases, and highly resistant to chemicals and electric (18) .Eyeing this as a cheaply and easily reproduced construction material, a whirlwind of work (19) and the birth of (20) plastic and plastic-derivatives were born from camphor to celluloid to rayon; cellophane, polyvinyl chloride (or PVC、; styrofoam and nylon were soon to follow.
As
B．After
C．Before
D．While