several times, but he still doesn’t know how to do it properly.

A．Being shown                                              B．Having shown     

C．Having been shown                      D．I’ve shown him

________ several times, but he still doesn't know how to do it properly．

1. A.
   Being shown
2. B.
   Having shown
3. C.
   Having been shown
4. D.
   I've shown him

________ several times, but he still doesn't know how to do it properly.

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