rollercoaster
n. 过山车;剧烈起伏的事物
例句
KENYA has been on a rollercoaster.
肯尼亚坐上了云霄飞车。
It always becomes a rollercoaster of emotions.
这就往往变成了情绪的过山车。
Getting off the rollercoaster is one thing; being able to get on the next ride quite another.
从过山车上下来是一回事,而能够获得乘坐下一趟则是另一回事。