— We did not see him at the lecture yesterday．
— You _______ him, since I went to an international conference with him．

— We did not see him at the lecture yesterday．

— You _______ him, since I went to an international conference with him．

— We did not see him at the lecture yesterday．

     — You _______ him, since I went to an international conference with him．

       A．mustn’t have seen                                       B．can’t have seen

     C．couldn’t see                                               D．needn’t have seen

 — We did not see him at the lecture yesterday．

     — You ______ him, since I went to an international conference with him．

         A. mustn’t have seen                                   B. can’t have seen

     C. couldn’t see                                               D. needn’t have seen

— We did not see him at the lecture yesterday．
— You _______ him, since I went to an international conference with him．

1. A.
   mustn’t have seen
2. B.
   can’t have seen
3. C.
   couldn’t see
4. D.
   needn’t have seen

— We did not see him at the lecture yesterday．

     — You ______ him, since I went to an international conference with him．

       A. mustn’t have seen                          B. can’t have seen

     C. couldn’t see                                   D. needn’t have seen

— We did not see him at the lecture yesterday．

     — You _______ him, since I went to an international conference with him．

       A．mustn’t have seen                                       B．can’t have seen

     C．couldn’t see                                               D．needn’t have seen

---- We did not see him at the lecture yesterday．

---- You ______ him, since I went to an international conference with him．

A．mustn’t have seen                                B．can’t have seen

C．couldn’t see                                        D．needn’t have seen

— We did not see him at the lecture yesterday．
— You _______ him, since I went to an international conference with him．