| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] has [been] a key | 15 |
|
| 2 | [noun sg] has [been] a key | 11 |
|
| 3 | has [been] a key [noun] | 20 |
|
| 4 | has [been] a key [noun sg] | 20 |
|
