| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] [Wh pn] have been exposed to | 8 |
|
| 2 | [noun] who [verb] been exposed to | 8 |
|
| 3 | [noun pl] [Wh pn] [verb] been exposed to | 6 |
|
| 4 | [noun] [Wh pn] [vb past] been exposed to | 5 |
|
| 5 | [noun] [Wh pn] had been exposed to | 5 |
|
