He became an actor at a very young age but it was nearly 20 years ______ he became famous.

    A. until                       B. when                     C. before                   D. that

He became an actor at a very young age but it was nearly 20 years ________ he became famous．

1. A.
   until
2. B.
   when
3. C.
   before
4. D.
   that

He became an actor at a very young age but it was nearly 20 years ______ he became famous.

A．until     B．when            C．before            D．that