| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] which [vb past] [be] introduced | 9 |
|
| 2 | [noun sg] which [vb past] [be] introduced | 8 |
|
| 3 | which [vb past] [be] introduced [prep] | 11 |
|
| 4 | which [vb past] [be] introduced [prep] | 11 |
|
