Ielts reading recent actual tests (2016 2017) with answers published by ieltsmaterial com

24 | 
P a g e
 
A favorable perfumes are made from ornamental flowers 
B traditional floriculture industry needs reform. 
C genetic operation on scent can make vast profit. 
D Scent plays a significant role in Ornamental industry. 
13. What is weakness of genetic experiments on fragrance? 
A Linalool level is too low to be smelt by nose 
B no progress made in linalool emission 
C experiment on tobacco has a better result 
D transgenic plants produce intense scent 
SECTION 2
 
You should spend about 20 minutes on Questions 14-26
，
which are based on Reading 
Passage 2 below. 
The Development of Plastics
A 
When rubber was first commercially produced in Europe during the nineteenth century, 
it rapidly became a very important commodity, particularly in the fields of transportation 
and electricity. However, during the twentieth century a number of new synthetic 
materials, called plastics, superseded natural rubber in all but a few applications. 
B 
Rubber is a polymer 
— a compound containing large molecules that are formed by the 
bonding of many smaller, simpler units, repeated over and over again. The same bonding 

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25 | 
P a g e
 
principle 
一
polymerisation
一
underlies the creation of a huge range of plastics by the 
chemical industry. 
C 
The first plastic was developed as a result of a competition in the USA. In the 1860s, 
$10,000 was offered to anybody who could replace ivory 
— supplies of which were 
declining 
— with something equally good as a material for making billiard balls. The prize 
was won by John Wesley Hyatt with a material called celluloid. Celluloid was made by 
dissolving cellulose, a carbohydrate derived from plants, in a solution of camphor 
dissolved in ethanol. This new material rapidly found uses in the manufacture of products 
such as knife handles, detachable collars and cuffs, spectacle frames and photographic 
film. Without celluloid, the film industry could never have got off the ground at the end of 
the 19th century. 
D
Celluloid can be repeatedly softened and reshaped by heat, and is known as a 
thermoplastic. In 1907 Leo Baekeland, a Belgian chemist working in the USA
，
invented 
a different kind of plastic by causing phenol and formaldehyde to react together. 
Baekeland called the material Bakelite, and it was the first of the thermosets' plastics that 
can be cast and moulded while hot, but cannot be softened by heat and reshaped once 
they have set. Bakelite was a good insulator, and was resistant to water, acids and 
moderate heat. With these properties it was soon being used in the manufacture of 
switches, household items, such as knife handles, and electrical components for cars. 
E 
Soon chemists began looking for other small molecules that could be strung together 
to make polymers. In the 1930s, British chemists discovered that the gas ethylene would 
polymerise under heat and pressure to form a thermoplastic they called polythene. 
Polypropylene followed in the 1950s. Both were used to make bottles, pipes and plastic 
bags. A small change in the starting material 
一
replacing a hydrogen atom in ethylene 
with a chlorine atom 
— produced PVC (polyvinyl chloride) 
，
a hard, fireproof plastic 
suitable for drains and gutters. And by adding certain chemicals, a soft form of PVC could 
be produced, suitable as a substitute for rubber in items such as waterproof clothing. A 
closely related plastic was Teflon, or PTFE (polytetrafluoroethylene). This had a very low 
coefficient of friction, making it ideal for bearings, rollers, and non-stick frying pans. 

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