| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [v-ing] [prep] be [adv] | 1034 |
|
| 2 | [prep] be [adv] difficult | 96 |
|
| 3 | [v-ing] [prep] be difficult | 51 |
|
| 4 | [v-ing] [prep] [adv] difficult | 6 |
|
