foot
The English word 'foot' has more than one meaning. In the United States, one meaning is a unit of measurement equal to 12 inches, or 0.3 meters. We use feet to measure height, length and short distances. Today's question is about when to use the plural or singular form. It comes from Wéifēng of China.
英语单词foot不止有一个意思。在美国，foot指测量单位，等于12英寸，或0.3米。我们用feet来测量高度、长度和短程距离。今天的问题是何时使用复数或单数形式。问题来自中国的Weifeng。
For the unit of measurement, we often use the singular form even when we are talking about more than one foot. This can make things confusing for learners.
作度量单位时，我们常使用单数形式，即使我们谈论的是不止一英尺。这会让学习者感到困惑。
feet
Luckily, there are three easy rules that can help:
幸运的是，这里有三个简单的规则可以帮助你：
1. When used as an adjective, we use 'foot,' which is the singular form. Let's hear some examples:
当用作形容词时，我们用foot，这是单数形式。我们来听几个例句：
Here, the adjective is '15-foot' and it describes the noun 'tree.' Here's another:
这里的“15-foot”是形容词，它形容的是名词“tree”。还有一个例子：
Here, the adjective '10-foot' describes the noun 'ladder.'
形容词
这里的形容词“10-foot”形容名词“ladder”。
Notice that both 15-foot and 10-foot come before the noun and there is a hyphen between the words. A hyphen is needed when a unit of measurement acts as an adjective.
注意15-foot和10-foot都放在了名词前，而且单词之间有连字符。当度量单位用作形容词时，需要加上连字符。
2. When used as a noun, we use the plural form: feet. Take a listen:
当用作名词时，我们用复数形式feet。来听一下：
Here, the noun is '15 feet' and the adjective is 'high.'
这里的“15 feet”是名词，形容词是“high”。
Here, the noun is '10 feet' and the adjective is 'tall.' Notice that the noun form does not use a hyphen.
这里的“10 feet”是名词，形容词是“tall”。注意，名词形式不使用连字符。
名词
These two rules also apply to many other units of measurement.
这两个规则也同样适用于很多其他度量单位。
3. Lastly, we usually use the singular form when talking about a person's height. This is an exception to the plural noun rule in number 2. Here's an example:
3. 最后，我们通常用单数形式谈论人的身高。这是第2条名词复数规则的一个例外。这里有个例子：
This is a common way of saying, 'I am 5 feet 6 inches tall.'
这是个常见的说法，“我身高是5英尺6英寸。”
However, when the person's height is an exact number of feet --without inches -- we use the plural form.
但是，当一个人的身高是精确的英尺数字时——没有英寸——我们使用复数形式。
The addition of 'tall' is not required in everyday conversation.
在日常对话中不需要加“tall”这个词。
表示其他意思时
For all other meanings of 'foot,' we use 'foot' for the singular form and 'feet' for the plural.
作为其他意思时，我们用“foot”表示单数，用“feet”表示复数形式。
