difficulties
词形变化：
同义词：
trouble | obstacle | hurdle | hardship | complexity | intricacy | adversity | complication | trickiness | problem | snag | predicament | misfortune | impediment | emergency | stumbling block | obstruction | annoyance | effort | struggle | hitch | exertion | strain | embarrassment | knot | weight | pest | crossing | mishap | penalty | delicacy | grief | misunderstanding | plight | vicissitude | rigor | difficultness |
反义词：
ease | simplicity |