| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | had [vb pp] a letter | 51 |
|
| 2 | had [vb pp] a letter | 51 |
|
| 3 | had received a letter | 17 |
|
| 4 | had written a letter | 12 |
|
| 5 | had sent a letter | 5 |
|
