| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | must have been [vb pp] [prep] | 237 |
|
| 2 | have been [vb pp] [adv prt] [prep] | 220 |
|
| 3 | must have [vb pp] [adv prt] [prep] | 68 |
|
| 4 | must have been [vb pp] [adv prt] | 41 |
|
| 5 | must have been [adv prt] [prep] | 19 |
|
