| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | had been [verb] on for | 32 |
|
| 2 | had been [v-ing] on for | 27 |
|
| 3 | had been go on for | 23 |
|
| 4 | had been going on for | 23 |
|
| 5 | had been [vb pp] on for | 5 |
|
