| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | had be [v-ing] for several [noun pl] | 10 |
|
| 2 | had been [v-ing] for several [noun] | 10 |
|
| 3 | had be [v-ing] for several years | 5 |
|
| 4 | had be [v-ing] for several year | 5 |
|
