Grammar focus The Past Indefinite Tense

Task 1. Read the sentences. Find the verbs, tell what grammar tense they are used in. Build up a negative form, a general and a special question to each sentence according to the model:

Model: Nuclear fusion in stars converted hydrogen and helium into the other elements found in the universe.

A negative form: Nuclear fusion in stars didn’t convert hydrogen and helium into the other elements found in the universe.

A general question: Did nuclear fusion in stars convert hydrogen and helium into the other elements found in the universe?

A special question: What did nuclear fusion in stars convert into the other elements found in the universe?

1. The debris from the explosion (the Big Bang) - hydrogen and helium began to cool and condense into the first stars and galaxies.

2. The bodies of our solar system evolved from an enormous rotating cloud called the solar nebula.

3. The solar nebula consisted of microscopic dust grains and the ejected matter of long-dead stars.

4. Nuclear fusion in stars converted hydrogen and helium into the other elements found in the universe.

5. Nearly 5 billion years ago a huge cloud of gases and minute grains of heavier elements began to contract slowly due to the gravitational interactions among its particles.

Task 2. Read the following text. Find the verbs in the Past Indefinite Tense. Build up 5 special questions to the sentences with the verbs in the Past Indefinite Tense. Translate the text into Ukrainian. Transcribe and translate the following words: nebula, carbon dioxide, ammonia, methane, hydrogen, helium, meteorite, silicon, calcium, sodium.

During the collapse, gravitational energy was converted to thermal energy, causing the temperature of the inner portion of the nebula to rise dramatically. At these high temperatures, the dust grains broke up into molecules and extremely energetic atomic particles. However, at distances beyond the orbit of Mars, the temperatures probably remained quite low. At –200 °C, the tiny particles in the outer portion of the nebula were likely covered with a thick layer of ices made of frozen water, carbon dioxide, ammonia, and methane. The disk-shaped cloud also contained appreciable amounts of the lighter gases hydrogen and helium.

The formation of the Sun marked the end of the period of contraction and thus the end of gravitational heating. Temperatures in the region where the inner planets now reside began to decline. The decrease in temperature caused those substances with high melting points to condense into tiny particles that began to join together. Materials such as iron and nickel and the elements of which the rock-forming minerals are composed—silicon, calcium, sodium, and so forth—formed metallic and rocky clumps that orbited the Sun. Repeated collisions caused these masses to join together into larger asteroid-size bodies, called planetesimals, which in a few tens of millions of years accreted into the four inner planets we call Mercury, Venus, Earth, and Mars. Not all of these clumps of matter were incorporated into the planetesimals. Those rocky and metallic pieces that remained in orbit are called meteorites when they survive an impact with Earth.