| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it be a problem | 148 |
|
| 2 | it [be] a problem | 148 |
|
| 3 | it [is] a problem | 123 |
|
| 4 | it 's a problem | 68 |
|
| 5 | it is a problem | 55 |
|
| 6 | it [was/were] a problem | 22 |
|
| 7 | it was a problem | 21 |
|
