Rule 6. There are also three degrees of adverbs. In formal usage, do not drop the -ly from an adverb when using the comparative form.
Incorrect: She spoke quicker than he did.
Correct: She spoke more quickly than he did.
Incorrect: Talk quieter.
Correct: Talk more quietly.
Rule 7. When this, that, these, and those are followed by a noun, they are adjectives. When they appear without a noun following them, they are pronouns.
Examples:
This house is for sale.
This is an adjective.
This is for sale.
This is a pronoun.
Incorrect: She spoke quicker than he did.
Correct: She spoke more quickly than he did.
Incorrect: Talk quieter.
Correct: Talk more quietly.
Rule 7. When this, that, these, and those are followed by a noun, they are adjectives. When they appear without a noun following them, they are pronouns.
Examples:
This house is for sale.
This is an adjective.
This is for sale.
This is a pronoun.