| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | forms [vb mod] be obtained from | 17 |
|
| 2 | forms can be obtained [prep] | 16 |
|
| 3 | forms may be obtained [prep] | 6 |
|
| 4 | forms [vb mod] be obtained by | 5 |
|
