Astronomers at the University of California discovered one of the most distant ______

A．the service industry is relying more and more on the female work force
B．manufacturing industries are steadily increasing
C．people find it harder and harder to earn a living by working in factories
D．most of the job opportunities can now be found in the service industry

A．the difference between the employee and the employer has become insignificant
B．people' s traditional concepts about work no longer hold true
C．most people have to take part-lime jobs
D．people have to change their jobs from time to time