| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun prp] [be] [v-ing] | 19186 |
|
| 2 | [be] [v-ing] a | 13940 |
|
| 3 | [noun prp] [be] a | 9755 |
|
| 4 | [noun prp] [v-ing] a | 918 |
|
