Plural nouns.

a. The rules to make the plural in English are very easy. Generally, we just add –S to the singular noun.

                Singular              Plural

                table          >        tableS

computer  >      computerS

But there are some exceptions. Click here to see them:

http://www.edufind.com/english-grammar/plural-nouns/

Remember: the nouns ending in –f or –fe usually make the plural in –VES:

E.g.        Knife > kniVES

                Wolf > wolVES

                Scarf > scarVES

b. Now you know the rules. Complete this exercise:

…and these crosswords!

http://www.englisch-hilfen.de/en/exercises/nouns_articles/plural7.htm

http://www.englisch-hilfen.de/en/exercises/nouns_articles/plural8.htm