| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun sg] had be [v-ing] on | 23 |
|
| 2 | [noun sg] had been [v-ing] on | 23 |
|
| 3 | [noun sg] had [been] [v-ing] on | 23 |
|
| 4 | [noun sg] had [be] working on | 10 |
|
