| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | had [been] [v-ing] on | 185 |
|
| 2 | had [been] [v-ing] [det] | 175 |
|
| 3 | [been] [v-ing] on [det] | 53 |
|
| 4 | had [been] on [det] | 11 |
|
