| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | had been [verb] on for some | 8 |
|
| 2 | had [been] [v-ing] on for some | 7 |
|
| 3 | had [been] going on for some | 6 |
|
| 4 | had [been] go on for some | 6 |
|
