1.复数的　of or having this form
2.A 不止一个　of more than one

　Here you should use plural pronoun.　这里你应该用复数代词。
　A plural marriage is forbidden by many countries.　一夫多妻，一妻多夫制被许多国家禁止。
　"Boy" is singular, and "boys" is plural. boy　是单数， boys是复数。

U 复数，复数形式　form of a noun or verb which refers to more than one person or thing

For example, "dogs" is the plural of "dog".例如：dogs是dog的复数。
　The verb should be in the plural, e. g. "have" in "they have".　这个动词应用复数形式，如：they have中的have.

［反义词］ adj. singular
［词源］古法语plurel（更多的）