| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | had [been] [verb] on | 226 |
|
| 2 | had [been] [v-ing] on | 101 |
|
| 3 | had [been] working [adv] | 47 |
|
| 4 | have [been] working on | 47 |
|
| 5 | [verb] [been] working on | 47 |
|
| 6 | [vb past] [been] working on | 19 |
|
| 7 | had [be] working on | 16 |
|
| 8 | had [been] work on | 16 |
|
