Multiple choice

Directions: Fill in the blank with the most appropriate of the given options.

Although thunder and lightning are produced at the same time, light waves travel faster _____, so we see the lightning before we hear the thunder.

  1. than sound waves do

  2. than sound waves are

  3. than are sound waves

  4. than sound waves ever have

  5. than sound waves are travelling
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When comparing two nouns with different verbs, the auxiliary 'do' is needed to avoid repetition. 'Light waves travel faster than sound waves do' is correct because 'do' substitutes for 'travel'. Other options either use incorrect forms ('are', 'have') or add unnecessary words.

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