To change the words in bold to mean more than one, you need to convert the singular nouns to their plural forms. Here's how you do it:
The dog is chewing the bone. - The plural form of 'dog' is 'dogs', and the plural form of 'bone' is 'bones'. The correct sentence is: The dogs are chewing some bones.
The friend is opening a box. - The plural form of 'friend' is 'friends', and the plural form of 'box' is 'boxes'. The correct sentence is: The friends are opening some boxes.
I can see a fox playing with a rabbit. - The plural form of 'fox' is 'foxes', and the plural form of 'rabbit' is 'rabbits'. The correct sentence is: I can see two foxes playing with two rabbits.
The student is sitting on a bench. - The plural form of 'student' is 'students', and the plural form of 'bench' is 'benches'. The correct sentence is: The students are sitting on benches.
The doll is wearing a pink dress. - The plural form of 'doll' is 'dolls', and the plural form of 'dress' is 'dresses'. The correct sentence is: The dolls are wearing pink dresses.
When forming plural nouns, often you just need to add 's' or 'es'. Words ending in 'x', 'sh', 'ch', 'ss', or 'z' typically require 'es' to be added to make them plural. Understanding these rules helps you correctly form plurals in English.