| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | then [vb infin] [art] | 604 |
|
| 2 | [prep] then [art] | 372 |
|
| 3 | [prep] [vb infin] [art] | 80 |
|
| 4 | [prep] then [vb infin] | 48 |
|
