| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] [verb] been [prep] operation [prep] | 23 |
|
| 2 | [noun] [verb] been in operation [prep] | 23 |
|
| 3 | [noun] have been [prep] operation [prep] | 23 |
|
| 4 | [noun sg] [verb] been [prep] operation [prep] | 19 |
|
| 5 | [noun] [vb -s] been [prep] operation [prep] | 14 |
|
| 6 | [noun] has been [prep] operation [prep] | 14 |
|
| 7 | [noun] [verb] been [prep] operation for | 13 |
|
| 8 | [noun] [vb past] been [prep] operation [prep] | 7 |
|
| 9 | [noun] had been [prep] operation [prep] | 7 |
|
| 10 | [noun] [verb] been [prep] operation since | 5 |
|
