| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | should [vb infin] [art] | 6887 |
|
| 2 | [vb infin] keep [art] | 203 |
|
| 3 | should keep [art] | 71 |
|
| 4 | should [vb infin] keep | 64 |
|
