| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have [be] operating for | 15 |
|
| 2 | have be operating for | 15 |
|
| 3 | have been operating for | 15 |
|
| 4 | have [been] operating for | 15 |
|
| 5 | has [be] operating for | 13 |
|
