7 Identify the relative clauses in these sentences. (Some contain more than one.) Rewrite them as participle clauses. 1 The word astronaut, which is formed from two Greek words, means 'star sailor'. 2 Only flights which reach an altitude of 100 km or more are considered space flights. 3 People who are chosen to become NASA astronauts have to complete a difficult training programme which lasts twenty months. 4 Astronauts who spend long periods in space do exercises which have been designed to keep them strong. 5 Spacecraft which intend to escape from Earth's gravity need to reach a speed of about 40,000 km/h. 6 People who watched the Apollo 13 mission on TV or who listened on the radio were very relieved when the astronauts returned safely. 7 James Lovell received the Exceptional Service Medal, which was awarded by NASA. 8 The film Apollo 13, which was made in 1995 and starred Tom Hanks, was nominated for many awards, which included nine Oscars.