| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | had [been] [v-ing] on | 101 |
|
| 2 | had been [v-ing] on | 101 |
|
| 3 | had [been] going on | 62 |
|
| 4 | had [been] working on | 16 |
|
| 5 | had [been] carrying on | 6 |
|
| 6 | had [been] sitting on | 5 |
|
