| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have [not/n't] been used for | 16 |
|
| 2 | have not [been] used for | 12 |
|
| 3 | had [not/n't] [been] used for | 6 |
|
| 4 | has [not/n't] [been] used for | 6 |
|
