1. I corrected the mistake founded by my teacher.
2. They showed us a new movie last week.
3. The movie shown was very boring
4. He keeps the letter written by his girlfriend.
5. They improved the method: the method improve was
very helpful in their work.
6. He took all the letters receiving that day.
7. No train arrived at the station during the night because of the snow
storm.
8. The theatre built in the 18* century is the most beautiful building in
the city.
13 Ice ages caused by different mechanisms are still a puzzle to scientists.
2. The last period of glaciation recorded in the geological history ended about twenty-five thousand years ago.
3. The age of the Sun can be estimated from the rate of the energy radiated
by it.
4. The total amount of salt contained in the sea can be measured.
5. In recent centuries it was learned that the earth is an imperfect sphere, slightly flattened at the poles and stretched at the Equator.
6. The orbits of the first artificial satellites, launched in 1957 and 1958,
showed that the flattening is less than had been thought.
7. Numerically the flattening is defined as the difference between the equatorial
diameter and the polar diameter, divided by the equatorial diameter.
8. The earth's shape, derived by Newton theoretically in his Principia in
1687, was a great help at that time.