I think Bill might win the competition.Yes, he's a bit of a dark horse, that one. Did you know he's already beaten the favorite?

I think Bill might win the competition.Yes, he's a bit of a dark horse, that one. Did you know he's already beaten the favorite?

意思跟中国的黑马可能是一样：不肯露出很多信息/不会露出自己的能力的的人。但是在英文里面，一定要等到证明那个人的能力的事情发生才可以说。