Although plural nouns in English usually end in an added -s, the words that modify them do not add -s.
The littleboys think that they are special. (Little and special modify boys.)
They want their busymothers to buy them newtoys every week. (Busy modifies mothers; new modifies toys.)
The sentences above show that there is usually no plural form for modifiers in English. The exceptions are the modifiers this and that, which have plural forms:
This little boy thinks that he is special These little boys think that they are special.
He wants thattoy. He wants thosetoys.
Be especially careful to choose correctly between the singular this and the plural these. They are pronounced very differently. Get a native English-speaker to help you hear the difference between these forms, so that you will have an easier time showing that difference in your writing.