| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [ex0] have been [adv] [det] research | 7 |
|
| 2 | [ex0] has been [adv] [det] research | 7 |
|
| 3 | there have been [adv] [det] research | 7 |
|
| 4 | [ex0] have been [adv] [det] research | 7 |
|
| 5 | [ex0] have been [adv] little research | 5 |
|
