如果两个人的关系不好，可以用英语表达为 "they don't get along well" 或者 "they have a strained relationship."

"Get along well" 表示两个人相处融洽，而 "strained relationship" 表示两个人的关系紧张。

下面是一些例句及其中文翻译：

They don't get along well because they have very different personapties. 他们个性不同，所以相处不是很愉快。

Their strained relationship is caused by a misunderstanding that happened years ago. 他们之间关系紧张是由多年前的一次误解引起的。

Despite their differences, they try to get along for the sake of their children. 尽管他们有很多分歧，但为了孩子们的福利，他们还是尽力和睦相处。