| Share | Phrase |
|---|
| 18.50% | troublesome [functioning] it |
| 17.00% | troublesome [functioning] operation |
| 16.72% | troublesome [functioning] spark |
| 13.76% | troublesome [functioning] maintenance |
| 11.94% | troublesome [functioning] work |
| 6.15% | troublesome [functioning] problem |
| 5.89% | particularly troublesome |
| 5.06% | troublesome [functioning] become |
| 4.94% | very troublesome |