| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | who [vb past] served as [noun] [prep] | 5 |
|
| 2 | [Wh pn] had served as [noun] [prep] | 5 |
|
| 3 | [Wh pn] [vb past] served as [noun] [prep] | 5 |
|
