These engines are quite problematic to fix. A repair is likely to be expensive.
onerous /ˈoʊnərəs/This system is very onerous and takes a long time to learn.
complicatedThis surgery is extremely complicated.Very few surgeons have the necessary experience to do it.
painfulMost people say the application process is long and painful.
challengingThis trek will be challenging. Make sure you bring the survival gear.
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