| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | been [verb] a | 2593 |
|
| 2 | been [v-ing] a | 1008 |
|
| 3 | be operating a | 37 |
|
| 4 | [be] operating a | 37 |
|
| 5 | been operating [art] | 8 |
|
| 6 | been operate a | 7 |
|
| 7 | [been] operating a | 7 |
|
