Their marriage went downhill after the first child was born.

自第一个孩子出生后他们的婚姻便开始走下坡路了。

《牛津词典》

We picked up speed as we went downhill.

下山时我们的速度加快了。

youdao

After that, for me, the course went downhill.

这之后，对我来说，课程的事降到了谷底。

youdao

Life pretty much went downhill from there for many solar panel makers and their suppliers.

FORBES: Report: 180 Solar Panel Makers Will Disappear By 2015

The Vanderbilts sold the farm in 1986 to a developer, and it quickly went downhill.

FORBES: Under Armour CEO Kevin Plank And His Underdog Horse Farm

But from there it went downhill, Pakistan playing as if someone had pulled the plug on their innings.

BBC: Eoin Morgan seals England series win over Pakistan