| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb pp] at a lower | 29 |
|
| 2 | [v-ing] at a lower | 9 |
|
| 3 | [vb -s] at a lower | 8 |
|
| 4 | operate at a lower | 6 |
|
| 5 | [to-vb] at a lower | 5 |
|
