bull's eye 靶心，十环，正中红心

【例句】
The arrow flew off and hit the bull's eye.
箭离弦飞去，射中了那靶心。

There should be a sign saying River Trips The bull's eye was marked with a large red circle.
应该有一个环河旅行的标记，靶心是用一个大红圆环作标记的。