| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] had been [verb] | 19757 |
|
| 2 | [noun] had been [v-ing] | 2088 |
|
| 3 | [noun] have been operating | 43 |
|
| 4 | [noun] [verb] been operating | 43 |
|
| 5 | [noun] had been operate | 15 |
|
| 6 | [noun] had be operating | 8 |
|
| 7 | [noun] had [been] operating | 8 |
|
| 8 | [noun] had [be] operating | 8 |
|
| 9 | [noun] [vb past] been operating | 8 |
|
