SummarizationRead each of the following short paragraphs and complete the phrase or sentence that expresses the main idea of the paragraph. The first letter of the missing word is given before the blank.Paragraph 2It takes time for them to prepare for the great changes that occur in space. When the spaceship leaves the earth at tremendous speed, the astronauts feel as if they are being crushed against the space ship floor. Later, when they leave the zone of the earth‘s gravitation, they are unable to stay in one place.2. Problems for astronauts to o_______when traveling to space.
【正确答案】：overcome
【题目解析】：P147
