| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [Wh pn] [vb base] be exposed to | 5 |
|
| 2 | [Wh pn] [vb base] been exposed to | 5 |
|
| 3 | [Wh pn] [vb base] [been] exposed to | 5 |
|
| 4 | who [vb base] [be] exposed to | 5 |
|
