| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [Wh det] [vb past] [been] used [prep] [noun] | 6 |
|
| 2 | [Wh det] [vb past] been used [prep] [noun] | 6 |
|
| 3 | [Wh det] had [been] used [prep] [noun] | 6 |
|
| 4 | which [vb past] [been] used [prep] [noun] | 6 |
|
