| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must [vb infin] [be] think | 12 |
|
| 2 | must have [be] think | 12 |
|
| 3 | must [vb infin] been think | 12 |
|
| 4 | must [vb infin] be think | 12 |
|
| 5 | must [vb infin] [been] think | 12 |
|
| 6 | must [vb infin] [be] thinking | 11 |
|
