| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun sg] have be operating for | 6 |
|
| 2 | [noun sg] have [been] operating for | 6 |
|
| 3 | [noun sg] have been operating for | 6 |
|
| 4 | [noun sg] has [be] operating for | 5 |
|
