| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could [adv] [adv] [vb infin] | 2400 |
|
| 2 | could [adv] [vb infin] back | 130 |
|
| 3 | [adv] [adv] [vb infin] back | 81 |
|
| 4 | could [adv] [vb infin] back | 62 |
|
