| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] must [not/n't] be forgotten | 21 |
|
| 2 | [pron] must not [be] forgotten | 21 |
|
| 3 | [pron] must [not/n't] [be] forgotten | 21 |
|
| 4 | [pers pn] must [not/n't] [be] forgotten | 20 |
|
| 5 | it must [not/n't] [be] forgotten | 19 |
|
| 6 | it must [not/n't] [be] forgotten | 19 |
|
