| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [vb infin] at the | 84 |
|
| 2 | must [vb infin] at the | 84 |
|
| 3 | must look at the | 31 |
|
| 4 | must remain at the | 5 |
|
| 5 | must start at the | 5 |
|
