ninety

• 数词，表示九十个（人或物）的数量；是十的倍数中最后一个圆整数，位于一百之前。也可作名词、定语或代词使用。

The cardinal numeral representing the quantity of ninety units; the ninetieth positive integer following eighty-nine; a composite number (2×3²×5); the last round multiple of ten before one hundred, commonly used in counting, measurement, percentages, and age milestones. Also functions as a noun (denoting the symbol, quantity, or group of ninety), adjective/determiner (modifying nouns to indicate quantity), and pronoun (standing in for a plural noun phrase).

1. Cardinal numeral: the number 90A1formal

   Used to denote a quantity of ninety persons or things; the ninetieth positive integer in the sequence of natural numbers; a composite number (2×3²×5); represents a ninetyfold quantity in counting, mathematics, and everyday usage.

   基数词：数字90

   • There are ninety degrees in a right angle.
   • She scored ninety points on the final assessment.
   • Ninety plus ninety equals one hundred eighty.
   • The highway speed limit is ninety kilometers per hour.
   • He completed ninety percent of the project ahead of schedule.

2. Noun: the number, symbol, or group of ninetyA2formal

   A noun referring to the cardinal number ninety; the numeral symbol 90 or XC; a set, collection, or group consisting of ninety items; a playing card displaying ninety (in extended decks); a team or ensemble of ninety members; in currency, a ninety-unit banknote.

   名词：数字、符号或九十的集合

   • The number ninety marks the approach to a centennial milestone.
   • Circle the nineties in this demographic chart.
   • The festival ensemble includes a ninety of performers.
   • In some card variants, the ninety is a high-value scoring card.
   • The annual registry lists a ninety of certified contractors.

3. Adjective/Determiner: amounting to ninetyA1formal

   Used attributively before a noun to indicate that the quantity or number of the noun is ninety; modifies plural countable nouns to specify exact quantity.

   数量词/形容词：九十的

   • They booked a ninety-week postgraduate research program.
   • We need ninety additional access badges for the conference.
   • The experimental protocol requires ninety milliliters of the reagent.
   • She has ninety years of combined institutional experience.
   • Ninety international delegations participated in the climate summit.

4. Pronoun: ninety people or things (plural)B1formal

   Used as a pronoun to refer to ninety previously mentioned or understood persons or things; takes plural verb agreement.

   代词：九十个人或事物

   • Nine hundred applied, but only ninety were selected for the fellowship.
   • I invited seven hundred guests; ninety confirmed their attendance.
   • How many seats should we reserve? — Ninety will be ideal.
   • Several companies submitted proposals, but ninety advanced to the final evaluation round.
   • Of the manuscripts evaluated, ninety were accepted for publication.