Singular and Plural Nouns

A noun names a person, place, thing, or idea.

Usually, the first page of a grammar book tells you about nouns. Nouns give names of concrete or abstract things in our lives. As babies learn "mom," "dad," or "milk" as their first word, nouns should be the first topic when you study a foreign language.

For the plural form of most nouns, add s.

• bottle - bottles
• cup - cups
• pencil - pencils
• desk - desks
• sticker - stickers
• window - windows

For nouns that end in ch, x, s, or s sounds, add es.

• box - boxes
• watch - watches
• moss - mosses
• bus - buses

For nouns ending in f or fe, change f to v and add es.

• wolf - wolves
• wife - wives
• leaf - leaves
• life - lives

Some nouns have different plural forms.

• child - children
• woman - women
• man - men
• mouse - mice
• goose - geese

Nouns ending in vowels like y or o do not have definite rules.

• baby - babies
• toy - toys
• kidney - kidneys
• potato - potatoes
• memo - memos
• stereo - stereos

A few nouns have the same singular and plural forms.

• sheep - sheep
• deer - deer
• series - series
• species - species

Thanks for : http://www.talkenglish.com/grammar/singular-plural-nouns.aspx