| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | studies which [vb base] [vb pp] [prep] | 7 |
|
| 2 | studies which [vb base] [vb pp] [prep] | 7 |
|
| 3 | studies which have [vb pp] [prep] | 7 |
|
| 4 | studies which [vb base] looked [prep] | 5 |
|
