onerous
adjective formal uk/ˈəʊ.nər.əs/ us/ˈɑː.nɚ.əs/
繁重的；麻烦的；艰巨的
difficult to do or needing a lot of effort
the onerous task of finding a peaceful solution 寻找和平解决方案的艰巨任务
She found the duties of motherhood onerous. 她发现做妈妈任务艰巨。
Synonyms: burdensome taxing