| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb -s] been [verb] | 40418 |
|
| 2 | [vb -s] been [v-ing] | 4747 |
|
| 3 | [verb] been operating | 92 |
|
| 4 | [vb -s] been operate | 47 |
|
| 5 | [vb -s] [been] operating | 42 |
|
| 6 | [vb -s] [be] operating | 42 |
|
| 7 | [vb -s] be operating | 42 |
|
