| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have [adv] been a source | 12 |
|
| 2 | has [adv] been a source | 9 |
|
| 3 | [vb -s] [adv] been a source | 9 |
|
| 4 | [verb] long been a source | 5 |
|
| 5 | [verb] always been a source | 5 |
|
