Beth Let's start by looking at your example with 'wall' and 'walls'.
In a castle, there is usually more than one wall, so we use the plural form by adding -s, 'walls'. 'Castle walls' refers to the individual walls that make up a castle, and often the external ones.
那么,我们现在来对比一下 “castle walls” 中的名词 “walls” 与 “The Great Wall of China(长城)” 中的单数 “wall”。
Beth 'The Great Wall of China' actually had a series of walls that were built throughout history but the English name doesn't reflect this. And this might be because when the wall was first named in English, they didn't know that there was more than one wall.
Jiaying “中国的万里长城(The Great Wall of China)” 在修建时有多道城墙。但它的英文名称并没有反应这一点:“wall” 在这里是单数。这可能是因为人们最初用英语命名万里长城的时候,并不知道它有不止一道墙。
Beth That's right. So, it's possible that the name is a mistake.
Jiaying 刚刚我们回答了第一个问题,下面咱们来讲一讲英语中有关名词单复数的知识点。
Beth When we talk about one thing, we use the singular form of the noun.