gain/ɡeɪn/ v 赢得 n增值，好处

多指通过努力而有所收获，得到的结果。获得了好处是不是就“增值了”。

He gained a lot of knowledge from his travels。

增值

earn/ɜːn/ v 赚

就是赚钱！！

She earns a high salary in her new job.高薪

就是赚钱

acquire/əˈkwaɪə(r)/ v 获得

学会的技能、知识、或者获得财产。

He acquired a new language throught years of study.

She has acquired a good knowledge of English.她英语已经学的很好了

The company has just acquired new premises.公司购买了新办公大楼（财产）

obtain/əbˈteɪn/ v 获得，赢得，适用

通过特定手段、途径获得某物。更加抽象。ob-强调，tain-拿住，已经取得了就是获得，赢得（pertain 适用，存在；contain 包含）

She obtained permission to enter the building。

to obtain advice/information/permission

These conditions no longer obtain. 这些条件不再适用

以上四个词，很多情况下可以互换！不要太纠结！