他写了一封礼貌的谢绝信，婉拒了对方的晚宴邀请。

He wrote a polite letter of ___decline for the dinner invitation.

这颗恒星的赤纬是23度。

The star's ___declination is 23 degrees.

小路沿着一个平缓的下坡通向湖边。

The path follows a gentle ___decline down to the lake.