| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | there have been [det] studies | 15 |
|
| 2 | there [vb base] been [det] studies | 15 |
|
| 3 | there have been [det] studies | 15 |
|
| 4 | there [verb] been few studies | 6 |
|
| 5 | there [verb] been many studies | 6 |
|
