| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | he had difficulty [prep] [v-ing] | 14 |
|
| 2 | he had difficulty [prep] [v-ing] | 14 |
|
| 3 | he had difficulty in [v-ing] | 14 |
|
| 4 | he had difficulty in [v-ing] | 14 |
|
