This computer doesn’t work properly, because the operating system has          .

    A．broken up                        B．broken down

    C．broken out                       D．broken away

This computer doesn’t work properly, because a certain virus has ____ the operating system.

　 A. broken up　　 B. broken down　 C. broken out　　 D. broken away

This computer doesn’t work properly, because the operating system has         .

1. A.
   broken up
2. B.
   broken down
3. C.
   broken out
4. D.
   broken away

This computer doesn’t work properly, because the operating system has         .