| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [modal v] [be] [v-ing] | 15842 |
|
| 2 | [prep] [be] [v-ing] | 8008 |
|
| 3 | [modal v] [prep] [be] | 5048 |
|
| 4 | [modal v] [prep] [v-ing] | 80 |
|
