| No | Pattern | Freq | Relations |
|---|---|---|---|
| 31 | there [vb base] been instance | 7 |
|
| 32 | there [vb base] been studies | 6 |
|
| 33 | there [vb base] been study | 6 |
|
| 34 | there [vb base] been improvement | 5 |
|
| 35 | there [vb base] been fluctuation | 5 |
|
| 36 | there [vb base] been difference | 5 |
|
| 37 | there [vb base] been differences | 5 |
|
| 38 | there [vb base] been improvements | 5 |
|
| 39 | there [vb base] been fluctuations | 5 |
|
