| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it must [adv] have been | 15 |
|
| 2 | it must [adv] have [be] | 15 |
|
| 3 | it must [adv] have [been] | 15 |
|
| 4 | it must [adv] have [be] | 15 |
|
| 5 | it must [adv] have be | 15 |
|
| 6 | it must [adv] have [be] | 14 |
|
