downhill from here 从此都是下坡路；自此每况愈下；从此每况愈下

【例句】
Yes, it feels like it's downhill all the way from here.
的确，感觉上就好像从现在开始，一切每况愈下。

The route is all downhill from here to the finish.
从这里一直到结束都是下山的路了。