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