| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could [vb infin] [verb] a pin drop | 7 |
|
| 2 | could have [verb] a [noun] drop | 7 |
|
| 3 | could [vb infin] [vb pp] a [noun] drop | 7 |
|
| 4 | could [vb infin] heard a [noun] drop | 7 |
|
| 5 | could [vb infin] [verb] a pin drop | 7 |
|
| 6 | could [vb infin] hear a [noun] drop | 7 |
|
| 7 | could [vb infin] [verb] a [noun sg] drop | 7 |
|
