| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | there must [vb infin] been a [noun] | 49 |
|
| 2 | there must have been a [noun] | 49 |
|
| 3 | there must have been a [noun] | 48 |
|
| 4 | there must [verb] been a [noun sg] | 46 |
|
| 5 | there must [verb] been a time | 7 |
|
| 6 | there must [verb] been a time | 7 |
|
