| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] be [vb pp] clean | 17 |
|
| 2 | to [be] [vb pp] clean | 16 |
|
| 3 | [prep] [be] [vb pp] clean | 16 |
|
| 4 | to [be] [vb pp] clean | 16 |
|
| 5 | [prep] [be] kept clean | 11 |
|
