SORU: aşağıdaki parçada numaralanmış yerlereuygun düşen sözcük ya da ifadeyi bulunuz
The humble plastic bottle is now one of the most
commonly recycled objects. However, it was the
cheapness and durability of the product that (17)---- its
popularity over glass bottles. Nathaniel Wyeth, a US
engineer, worked on the invention (18)---- almost a
decade. When he asked a colleague if plastic might be
used to store carbonated beverages (19)---- coke, he
was told that they would explode. A series of early
experiments proved that carbonated beverages caused
the plastic to expand. Obviously, the plastic was too
weak, but it (20)---- if the long strands of molecules that
form plastic were made up together. Wyeth knew that
nylon gets stronger when its molecules are stretched
and aligned, and he developed a pre-formed mold.
(21)---- initial results were far from successful and it took
10,000 attempts to solve that problem, he finally
replaced the nylon with polyethylene-terphathalate
(PET) – an artificial substance used to make materials
for packaging food, including plastic drink bottles – and
the bottle was quickly taken up by the booming soft
drink industry