| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | they [modal v] [be] [v-ing] | 1125 |
|
| 2 | [modal v] [be] [v-ing] back | 133 |
|
| 3 | they [be] [v-ing] back | 91 |
|
| 4 | they [modal v] [be] back | 67 |
|
