---How was your climbing on Mount Tai?

---I didn't believe I could do it ________ I got to the top.

1. A.
   until
2. B.
   unless
3. C.
   after
4. D.
   when

--How was your climbing on Mount Tai?

--I didn’t believe I could do it          I got to the top．

A．until         B．unless                C．a(chǎn)fter               D．when