| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have be [v-ing] [prep] | 6066 |
|
| 2 | must have be [prep] | 294 |
|
| 3 | must have be [v-ing] | 289 |
|
| 4 | must be [v-ing] [prep] | 161 |
|
