46.D The negotiations between them had broken down.
47.A It has reaped huge profits in recent years.
48.C Extra pay based on sales revenues.
49.A They are kept in the dark about many details of their job.
50.B Changing the pay system would cause the industry more problems.
Passage Two （太空垃圾）
51.D To improve traffic conditions in space.
52.C Regulate the launching of new satellites.
53.A Set international standards for the space flight industry.
54.D Make a thorough analysis of any possible addition to space debris.
55.B Develop technology to address the space debris problem.