| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | which has been used [prep] | 24 |
|
| 2 | which [vb -s] been used [prep] | 24 |
|
| 3 | which [vb -s] been used in | 8 |
|
| 4 | which [vb -s] been used for | 7 |
|
