Question

Fill in the blank with the comparative form of the adverb:
Planes can fly __________ than birds.

• A. highest
• B. higher
• C. high
• D. highestly

Answer 1

The correct option is B higher

Adverbs modify a verb, an adjective and sometimes another adverb in a sentence.
Some adverbs, like adjectives, have three degrees of comparison.
If the adverb is of one syllable, we form the comparative by adding er, and the superlative by adding est, to the positive; as, 'fast-faster-fastest'.
Adverbs ending in ly form the comparative by adding more and the superlative by adding most; as, 'swiftly-more swiftly-most swiftly'.
Here, Option B is correct as higher is the comparative form of high. Consequently, the other three options cancel out.