| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | who have been working [prep] | 29 |
|
| 2 | who had been working [prep] | 12 |
|
| 3 | who have been working on | 10 |
|
| 4 | who have been working in | 9 |
|
| 5 | who has been working [prep] | 8 |
|
| 6 | who have been working [prep] | 6 |
|
