When ________, the museum will be open to the public next year.

1. A.
   completed
2. B.
   completing
3. C.
   being completed
4. D.
   to be completed

When ___, the museum will be open to the public next year.

A. completed　　 　　　　　　　　　　 B. completing　　 　

C. being completed　　 　　　　　　　 D. to be completed

When____, the museum will be open to the public next year.

　　A.completing 　    B.completed 　　  C.being completed 　D.to be completed