| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [modal v] [be] [v-ing] back to | 44 |
|
| 2 | they [modal v] [be] [v-ing] to | 35 |
|
| 3 | they [be] [v-ing] back to | 20 |
|
| 4 | they [modal v] [be] [v-ing] back | 16 |
|
