| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have been at the forefront | 33 |
|
| 2 | have [been] at the forefront | 33 |
|
| 3 | has [been] at the forefront | 15 |
|
| 4 | have [been] at the forefront | 11 |
|
| 5 | had [been] at the forefront | 6 |
|
