arduous

arduous adj.

費勁的, 辛勤的, 險峻的

英英解釋:形容詞arduous:
1. characterized by toilsome effort to the point of exhaustion; especially physical effort
同義詞：backbreaking, grueling, gruelling, hard, heavy, laborious, operose, punishing, toilsome
2. taxing to the utmost; testing powers of endurance- F.D.Roosevelt
同義詞：straining, strenuous
3. difficult to accomplish; demanding considerable mental effort and skill