转两封比较有趣的信：

#Dear Mr. Firsten,

#An English second language student has asked a question that neither I nor colleagues can fully answer. We can say what is right and what isn't right, but we're not sufficiently able in this case to explain why and why not.

#The student's question:

#The word plural is defined as consisting of, containing, or pertaining to more than one. How about a fractional, decimal, or negative unit of a noun?

#Example: One/a degree, two degrees. Those are no problem.

#How about 1.1 degrees, 0.5 degrees, a half (or 1/2) degrees (?), 1.0 degree (?), 0 degrees (?), -3.5 degrees, -1 degrees

#Are they right?

#We suggested that the answer might lie in countable and uncountable nouns. This is a real conundrum for us. Why do people say, for example, It's zero degrees Celsius when zero is not a plural form?

#Thank you.

#Carolyn Samuel
#Montreal, Quebec, Canada

#Dear Ms. Samuel:

#Let's start with zero degrees. In this case, zero is another way to say the negative determiners no or any. As such, they can be used with a singular countable noun (no train/any train) or in a more general observation with a plural countable noun (no trains/any trains). You can say The thermometer registers no degrees or The thermometer doesn't register any degrees. By extension, people also use the word zero or the number 0: The thermometer registers zero/0 degrees.

#As for every fraction or decimal above or below one, you use the plural noun. People have a sense that if something is more than one, even if only a fraction more, it should be pluralized: ± 1.1 degrees/1¼ miles.

#The one aberration, if I can call it that, is when you write a decimal under one plus a noun such as degree (0.5˚). Even in such a case you still use a plural noun and say zero point five degrees. When written as a fraction, however (½˚), you use a singular noun and can say this in a variety of ways: a half a degree/a half of a degree/half a degree/half of a degree.

#For the most part, then, the most important points are that when you use zero + a noun or have a fraction or decimal together with one + a noun, you make the noun plural.

#Thank you for a great question, Ms. Samuel!