Into is 1 word.
2 words
It should be 2 words.
2
Green Day is 2 words.
I is 2 words. SPRAY-BUTTER
Two words.
1
No, one thing can be 1 or 2 words e.g NERVE_CELL. 2 words, 1 thing.
-1/2 or 1/-2 but most commonly -(1/2) (They all are the same)
2 words.
Countryside is 1 word.
Examples of words that change the base word to form the plural are: 1 goose; 2 geese 1 die; 2 dice 1 mouse; 2 mice 1 child; 2 children 1 man; 2 men 1 tooth; 2 teeth 1 foot; 2 feet