You use vicissitudes to refer to changes, especially unpleasant ones, that happen to someone or something at different times in their life or development.
例句
Whatever the vicissitudes of her past life, Jill now seems to have come through.不管过去经历了什么坎坷，吉尔现在似乎都已经挺过来了。
英汉词典释义
n.
变迁,世事变化
A man used to vicissitudes is not easily dejected.饱经沧桑,不易沮丧。He experienced several great social vicissitudes in his life.他一生中经历了几次大的社会变迁。