________ true events, the film follows the life of Ali, a world famous boxer in the US.

________ true events, the film follows the life of Ali, a world famous boxer in the US.

A．Being based on                         B．Basing on

C．Based on                              D．Having based on

________ true events, the film follows the life of Ali, a world famous boxer in the US.

1. A.
   Being based on
2. B.
   Basing on
3. C.
   Based on
4. D.
   Having based on