조동사+have pp

[잘나가는 학예사]

1. must have pp : -이었음에 틀림없다

   He must have told a lie.

2. can't  have pp : -이었을리가 없다

   He can't have read the difficult book.

3. should have pp : -했어야 했지만 하지 않았다.

  You should have studied for the test.

4. may have pp : -이었을지도 모른다

   She may have left already.