| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have been used for | 195 |
|
| 2 | has been used for | 62 |
|
| 3 | have been used for | 53 |
|
| 4 | had been used for | 36 |
|
| 5 | have been used for | 23 |
|
| 6 | to have been used for | 10 |
|
| 7 | 's been used for | 7 |
|
