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Exercises - Tenses

9. Even __________________, Rome served as a crossroads for people of a variety of ethnicities and cultures.

10. The Space Shuttle Challenger broke apart within 73 seconds __________________ it launched from Cape
Canaveral, Florida, on January 28, 1986.

G) In the following paragraph, some lines are correct, but some include a mistake. If the line is
right, put a tick next to it, but if there is a mistake, cross it out and write its correct form.

1 Without a doubt, the thing we need most in the summer heat is to keep ourselves cool. For __________
2 this reason, we sometimes are preferring staying in closed areas during the day, especially at prefer
3 noon; sometimes, we consume cold drinks and food, and sometimes we try to cool off by __________
4 using a fan. But when the air temperatures are too high, these methods may not work well __________
5 enough. At such moments, the air conditioner has come to the fore. Today, air conditioners __________
6 have became indispensable in summer months. __________
7 In ancient times, the Egyptians had tried methods such as hanging wet cloth in front of their __________
8 doors to keep themselves cool against the extreme heat. The Romans tried to cool off by __________
9 running the water they carried to the city with aqueducts over the walls of their houses. __________
10 Important developments in cooling the air took place when the 16th century. In 1758, the US __________
11 statesman and inventor Benjamin Franklin and Cambridge University professor John Hadley __________
12 were finding out in their experiments that the air could be cooled through the rapid evaporation of __________
13 some liquids. In the 1820s, British inventor Michael Faraday has discovered that he could cool __________
14 the air in his laboratory by compressing and liquefying ammonia under high pressure and __________
15 evaporating it. __________
16 In 1851, a doctor named John Gorrie was trying to cool the rooms with an ice basin suspended __________
17 from the ceiling to keep yellow fever patients cool. Ice was carried from frozen lakes and __________
18 streams in the United States to hospital rooms. To overcome this challenge, Gorrie had designed __________
19 a machine that created ice with the aid of a compressor. Due to financial difficulties, he __________
20 cannot sell the technology he developed, but his invention formed the basis of modern air __________
21 conditioning and refrigeration. __________

H) Use the Past Simple, Past Perfect, or Past Perfect Continuous forms of the verbs in parentheses
to complete the sentences.

1. Long before the Spaniards _________________ (explore) the Americas, indigenous peoples of pre-Hispanic
cultures _________________ (create) advanced civilisations in Mexico and South America.
2. Astronomers _________________ (observe) the irregular, jagged motions of the sun for many years, but in
1675, the Italian astronomer Giovanni Cassini _________________ (use) his own observations and those of
his predecessors to come up with Cassini’s Law.
3. Once the petrol reserves of the country _________________ (deplete), fuel prices _________________
(skyrocket), causing most people to be unable to drive.
4. Until the First World War _________________ (break out), none of the nations involved _________________
(attempt) to mobilise an army of millions of young men.

5. The publishing house _________________ (seek) a chance to put out a new book by its most celebrated
author, who _________________ (write) fifty books by 2020, when it finally _________________ (obtain) the
rights to publish his new novel.

6 . Representatives of the firm _________________ (yearn) for an opportunity to prove the viability of their ideas
for months before the council finally _________________ (give) them a chance.

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