| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | may [adv] have be [verb] | 248 |
|
| 2 | [modal v] [adv] have be [v-ing] | 151 |
|
| 3 | may [adv] [verb] be [v-ing] | 27 |
|
| 4 | may [adv] have [be] [v-ing] | 27 |
|
