| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must have been [prep] [art] [noun sg] | 54 |
|
| 2 | must have been [prep] [art] [noun sg] | 54 |
|
| 3 | must have been [prep] the [noun sg] | 36 |
|
| 4 | must have been in [art] [noun sg] | 24 |
|
| 5 | must have been [prep] a [noun sg] | 16 |
|
| 6 | must have been on [art] [noun sg] | 6 |
|
