| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it must have be [noun] | 39 |
|
| 2 | it must have [been] [noun] | 39 |
|
| 3 | it must have been [noun] | 39 |
|
| 4 | it must have [be] [noun] | 39 |
|
| 5 | it must have [be] [noun prp] | 26 |
|
| 6 | it must have [be] [noun sg] | 12 |
|
