Review of Tenses
- from Understanding and Using English Grammar, Workbook A, 2nd edition
Almost every part of the world (experience) HAS EXPERIENCED an earthquake
in recent years, and almost every part of the world (experience) WILL EXPERIENCE
earthquakes in the years to come. Since the ancient Chinese (begin) BEGAN to keep
records thousands of years ago, more than 13 million earthquakes (occur) HAVE
OCCURRED worldwide by some estimates.
What (cause) CAUSES earthquakes? Throughout time, different cultures
(develop) HAVE DEVELOPED myths to explain these violent earth movements.
According to a Japanese myth, a playful catfish lives in the mud under the earth.
Whenever it feels like playing, it (wave) WAVES its fat tail around in the mud. The
result? Earthquakes. From India comes the story of six strong elephants who (hold)
HOLD up the earth on their heads. Whenever one elephant (move) MOVES its head, the
earth trembles.
Nowadays, although scientists (know) KNOW more about the causes of
earthquakes, they still can't prevent the terrible damage.
One of the strongest quakes in this century (happen) HAPPENED in Anchorage,
Alaska, on March 24, 1964, at about six o'clock in the evening. When the earthquake
(strike) STRUCK that evening, many families (sit) WERE SITTING down to eat dinner.
People in the city (find, suddenly) SUDDENLY FOUND themselves in the dark because
most of the lights in the city went out when the earthquake occurred. Many people (die)
DIED instantly when tall buildings (collapse) COLLAPSED and (send) SENT tons of
brick and concrete crashing into the streets.
When (occur, the next earthquake) WILL THE NEXT EARTHQUAKE OCCUR
? No one really knows for sure.
Interestingly enough, throughout history, animals (help, often) OFTEN HELP
people to predict earthquakes shortly before they happen. At present, some scientists
(study) ARE STUDYING catfish because catfish swim excitedly just before an
earthquake. According to some studies, snakes, monkeys, and rodents (appear, also)
ALSO APPEAR to be sensitive to the approach of violent movement in the earth's
surface. Some animals seem to know a great deal more than humans about when an
earthquake will occur.
In recent years, scientists (develop) HAVE DEVELOPED many extremely
sensitive instruments. Perhaps someday the instruments (give) WILL GIVE us a
sufficiently early warning so that we can be waiting calmly in a safe place when the next
earthquake (strike) STRIKES.