are

名词 are:

1. a unit of surface area equal to 100 square meters
   同义词：ar

动词 be:

1. have the quality of being; (copula, used with an adjective or a predicate noun)
   同义词：be
2. be identical to; be someone or something
   同义词：be
3. occupy a certain position or area; be somewhere
   同义词：be
4. have an existence, be extant
   同义词：exist, be
5. happen, occur, take place
   同义词：be
6. be identical or equivalent to
   同义词：equal, be
7. form or compose
   同义词：constitute, represent, make up, comprise, be
8. work in a specific place, with a specific subject, or in a specific function
   同义词：be, follow
9. represent, as of a character on stage
   同义词：embody, be, personify
10. spend or use time
    同义词：be
11. have life, be alive
    同义词：be, live
12. to remain unmolested, undisturbed, or uninterrupted -- used only in infinitive form
    同义词：be
13. be priced at
    同义词：cost, be

1. Don't cry, you are a big boy now.
   别哭，你现在已经是大男孩了。
2. These people who were young fifty years back are now gray haired.
   50年前的年轻人，现在已经白发苍苍了。
3. Dark clouds are a sign of rain or snow.
   乌云是雨或雪将至的预兆。
4. There are 300 students or so in this middle school.
   这所中学大约有300个学生。
5. Love and hate are extremes.
   爱和恨是两个极端。
6. There are more than 5,000 adjectives in that dictionary.
   那本词典中有5000多个形容词。
7. You are just saying that.
   你只是说说而已。
8. Who do you think you are?
   你以为你是谁？

are

v.（动词）
Second person singular and plural and first and third person plural present indicative of be
be的第二人称单数和复数以及第一和第三人称复数现在陈述语气词

来源：
Middle English aren
中古英语 aren
from Old English aron * see er-
源自 古英语 aron *参见 er-

are
are 2

n.Abbr. a,a.（名词）缩写 a,a.
A metric unit of area equal to 00 square meters (9.' square yards).
公亩：面积的公制单位，等于00平方米(9.'平方码）

来源：
French
法语
from Latin 3rea [open space] * see area
源自 拉丁语 3rea [开放空间] *参见 area