| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | who had be [v-ing] for a | 7 |
|
| 2 | who had [been] [v-ing] for a | 7 |
|
| 3 | who had been [v-ing] for a | 7 |
|
| 4 | who had [be] [v-ing] for a | 7 |
|
