| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | how long do they [vb infin] | 13 |
|
| 2 | how long [verb] they [vb infin] | 13 |
|
| 3 | how long [vb base] they [vb infin] | 11 |
|
| 4 | how long do they [vb infin] | 11 |
|
