couple = 一对,一双
couples = 两对或以上
夫妇有几个不同翻译,couple(s) 是其中之一
比较精确的翻译是 married couple
例：
Tomorrow's dance is for couples only.You and Mary can go together as a couple.
其他翻译有
husband （丈夫） and wife （妻子）
spouses
better halves
mates
significant others
partners in life
等等