| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | would have been | 6970 |
|
| 2 | must have been | 3371 |
|
| 3 | may have been | 2861 |
|
| 4 | might have been | 2512 |
|
| 5 | could have been | 2479 |
|
| 6 | should have been | 1852 |
|
| 7 | will have been | 637 |
|
| 8 | 'd have been | 335 |
|
| 9 | can have been | 46 |
|
| 10 | 'll have been | 29 |
|
| 11 | shall have been | 24 |
|
| 12 | need have been | 15 |
|
