| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb mod] only [be] obtained | 26 |
|
| 2 | [vb mod] only be obtain | 26 |
|
| 3 | [vb mod] only [be] obtain | 26 |
|
| 4 | can only [be] obtain | 17 |
|
| 5 | could only [be] obtain | 7 |
|
