| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could be [vb pp] [adv prt] | 756 |
|
| 2 | could be [vb pp] [v-ing] | 178 |
|
| 3 | be [vb pp] [v-ing] [adv prt] | 72 |
|
| 4 | could be [v-ing] [adv prt] | 52 |
|
