| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have been operating [prep] [adv] | 7 |
|
| 2 | have been operate [prep] [adv] | 7 |
|
| 3 | have been operate for [adv] | 6 |
|
| 4 | have been operate for [adv] | 6 |
|
| 5 | has been operate [prep] [adv] | 5 |
|
