| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could have been [verb] for | 67 |
|
| 2 | [modal v] have been [v-ing] for | 53 |
|
| 3 | could have been [v-ing] [prep] | 29 |
|
| 4 | could have been [v-ing] [prep] | 29 |
|
| 5 | could [verb] been [v-ing] for | 10 |
|
| 6 | could [vb infin] been [v-ing] for | 10 |
|
| 7 | could have been [v-ing] for | 10 |
|
| 8 | could have [be] [v-ing] for | 9 |
|
| 9 | could have [been] [v-ing] for | 9 |
|
| 10 | could have be [v-ing] for | 9 |
|
| 11 | could have been [v-ing] for | 9 |
|
