| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [to-vb] at [adj] | 1942 |
|
| 2 | required [to-vb] [adj] | 592 |
|
| 3 | required at [adj] | 32 |
|
| 4 | required [to-vb] at | 29 |
|
