--- How did you like the concert last night?

--- I enjoyed it very much, but the dancers ______ a better job.

---How did you like the concert last night ?

---I enjoyed it very much, but the dancers ______ a better job．

1. A.
   could have done
2. B.
   must have done
3. C.
   could do
4. D.
   had done

--- How did you like the concert last night?
--- I enjoyed it very much, but the dancers ______ a better job.

1. A.
   could have done
2. B.
   couldn’t have done
3. C.
   could do
4. D.
   had done

—How did you like the concert last night ?

—I enjoyed it very much, but the dancers _____ a better job．

　　　 A．could have done　　　　　　　　　　 　　 B．must have done

　　　 C．could do　　　　　　　　　　　 　　　　 D．had done

—How did you like the concert last night?

—I enjoyed it very much, but the dancers ______ a better job.

A. could have done　 　 B. couldn’t have done　　 C. must do　　 D. must have done