| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun sg] systems which [modal v] [vb infin] | 7 |
|
| 2 | [noun] systems which [modal v] [vb infin] | 7 |
|
| 3 | systems which [modal v] [vb infin] [noun] | 5 |
|
