UNIT 2 SINGULAR AND PLURAL NOUNS

1. A singular noun stands for one person or thing.
   单数名词代表一个人或东西。

2. A plural noun stand for more than one person or thing.
   复数名词代表一个以上的人或东西。

3. Plural nouns are formed in several way:
    复数名词由几种方式构成：

• by adding "-s" to the singular nouns;

         在单数名词后面加“-s”；
         e.g. car = cars
                 tree = trees

• by adding "-es" ton nouns ending in "-s", "-sh", "-ch", "-x" and "-o";

         在词尾是“-s”，“-sh ”，“-ch”，“-x”和“-o”的名次后加“-es”；
         e.g. brush   = brushes
                watch  = watches

• by changing "-y" into "-ies"

        把词尾“-y”换成“-ies”；
        e.g. lady   = ladies
                 story  = stories

• by changing "-f" or "-fe"into "-ves"

        把词尾“-f ”或“fe”换成“-ves”；
         e.g. knife = knives
                  thief  = thieves

•  irregular forms;

         不规则的形式
         e.g. child   = children
                 mouse = mice

• same singular and plural form.

        复数形式保持不变
        e.g. sheep = sheep
                 deer   = deer

More exercises here

http://www.englisch-hilfen.de/en/exercises/nouns_articles/plural3.htm
http://www.englisch-hilfen.de/en/exercises/nouns_articles/plural.htm
http://www.englisch-hilfen.de/en/exercises/nouns_articles/plural4.htm
http://www.englisch-hilfen.de/en/exercises/nouns_articles/singular_plural.htm