| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | difficulty in [v-ing] [adv prt] the | 8 |
|
| 2 | difficulty in [verb] [adv prt] the | 8 |
|
| 3 | difficulty in [verb] [adv prt] the | 8 |
|
| 4 | difficulty in [verb] [adv prt] the | 6 |
|
