sour
meaning: If a relationship or someone's attitude sours, or if something sours it, it becomes unfriendly or unfavorable.
进阶篇：sour： 可以作形容词也可以作动词。作形容词, 它的常见意思是酸的, 馊的。作动词意思是恶化，使...变糟。从上面的英英解释中可以看出，sour既可以是及物动词也可以是不及物动词。不过在不及物动词中我们知道它更常作不及物动词。我们可以把 sour和之前学过的 compound 和 worsen 放在一起学习。《经济学人》在写某两个国家的关系恶化时，常常会用到 sour 这个词。下面通过几个例子来掌握这个词。
很多朋友关系是因为借钱而弄僵的，就可以说：
Many friendships sour over borrowed money.
在越南会谈之后，美国和朝鲜的关系再度恶化，可以说：
After the Vietnam talk, the relationship between the US and North Korea soured again.
印度和巴基斯坦在领土问题上的争议使得两国关系急转直下，我们就可以说：
The territorial dispute between India and Pakistan soured bilateral relations.
As our special report in this week's issue explains, superpower relations have soured.
The once-cordial relationship between Mr. Trump and Deutsche has soured.
Business confidence had soured and the housing market, so often a leading indicator of economic trouble, had sagged.
这句中的confidence 和 sour 这组搭配出现频率要远低于relationship/relations 和 sour 这组搭配
应用篇：
1） 翻译： 他和母亲的关系突然变得很僵。
His relationship with his mother soured all of a sudden.
2）造句：他们因为金钱方面意见不一致关系恶化。
Their relationship soured over financial disputes.
