| curve | 要查询的曲线。 | 
| index | 关键帧索引。 | 
TangentMode Returns the tangent mode.
Retrieves the right tangent mode of the keyframe at a specific index.
        The Curve Editor uses the keyframe tangent mode to automatically generate tangents.
另请参阅:AnimationUtility.GetKeyLeftTangentMode、AnimationUtility.GetKeyBroken。