toss-up

汉语翻译

n. 掷钱币, (成败各半的)相等机会

英语解释

名词 toss-up:

an unpredictable phenomenon同义词：tossup, even chance

例句

Both players are equally good so it's a toss-up (ie impossible to predict) who will win.那两个运动员不相上下，谁能取胜还很难说。