在现实生活中，我们经常看到有些人无论做什么，都是在一起的，也即形影不离，它指的是像形体和它的影子那样分不开，形容彼此关系密切，经常在一起，可用来形容关系非常密切的男女感情、亲情或友情等，感觉是不可分的。
在英语中表达”不可分的，形影不离“常用单词是 inseparable [ɪnˈseprəbl] 或 indivisible，它们分别是 separable 和 divisible 加否定前缀 in 得来的。其中 separable 和 inseparable 常用的搭配是：inseparable/ separable from sth，例如：
Our economic fortunes are inseparable from those of Europe.He firmly believes liberty is inseparable from social justice.The moral question is not entirely separable from the financial one.Character is not separable from physical form but is governed by it.Far from being separate, the mind and body form an indivisible whole.心智与身体绝不是分离的，它们形成了一个不可分割的整体。Even numbers are divisible by two.
习语 (like) two peas in a pod 有类似形影不离的意思，它的字面意思是”（像）豌豆荚里的两个豌豆“，用来比喻关系非常密切或非常相似甚至一样，例如：Stress and work are like two peas in a pod.We tend to view them as two peas in a pod.
表达”形影不离“还可以用习语 joined at the hip，字面意思虽是”在臀部连接“，但它跟臀部没有关系，它用来形容两个人的关系非常密切，经常形影不离或成双成对地出现：Every time I see Jenna, Kelli is right there with her. Those two are really joined at the hip these days.每次我见到珍娜，凯莉就在她身边。这两个人最近真正地形影不离。The couple who are almost joined at the hip in their 20s may have become quite distant in their 40s.这对在20多岁的时候几乎形影不离的夫妇，可能在40多岁的时候变得相当疏远了。Though we often work together, we're not joined at the hip.Sally and I are very much in love, but we are not joined at the hip, you know. We have our own personal lives and space.莎莉和我很相爱，但你知道，我们没有形影不离。我们有自己的私人生活和空间。
相信大家都听过”物以类聚，人以群分“，它用于比喻同类的东西常聚在一起，志同道合的人相聚成群，反之就分开，用英语表达是：birds of a feather flock together，例如：I knew you and John would get along well, seeing as you both enjoy science fiction so much. Birds of a feather flock together.我知道你和约翰会相处得很好，因为你们都很喜欢科幻小说。物以类聚，人以群分。I always thought Amy was pretentious, and now she's going out with that snobbish boy, Louis. Birds of a feather flock together.我一直认为艾米很自命不凡，现在她要和那个势利的男孩路易斯约会。物以类聚，人以群分。人只要实现了自我价值，就不枉此生。每个奔波于纷繁世界的人，都在寻找属于自己的世界和自己的知己，这也许也是生命存在的意义之一。
