A gruelling activity is extremely difficult and tiring to do.
例句
He had complained of exhaustion after his gruelling schedule over the past week...完成上周緊張的日程安排后，他抱怨自己累得筋疲力盡。This flight was more gruelling than I had expected.這次飛行比我預(yù)想的更累！
英漢詞典釋義
adj.
緊張的,激烈的;使極度疲勞的
a gruelling climb叫人筋疲力盡的攀登The recruits were put through a week of gruelling endurance tests.新兵要接受為期一周艱苦的耐力測(cè)試。
英英詞典釋義
Adjective
1. characterized by toilsome effort to the point of exhaustion; especially physical effort;
"worked their arduous way up the mining valley""a grueling campaign""hard labor""heavy work""heavy going""spent many laborious hours on the project""set a punishing pace"