| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] system have been [verb] [prep] | 33 |
|
| 2 | [noun] system have been [vb pp] [prep] | 33 |
|
| 3 | [noun] system have been [prep] [noun] | 5 |
|
| 4 | [noun] system have been [prep] [noun sg] | 5 |
|
