Multiple choice

Choose the option which best fits gap 19.

Directions: Fill in the gaps with the most appropriate option.

Ever since  Galileo pointed his homemade optical telescope towards the heavens, astronomers---18--------------------building instruments of increasing power and sophistication ---------19--------------------to observe the universe. Hale telescope on Mount Palamar in Southern California can   detect objects a million times smaller than Galileo’s device -----21--------, they still have their limitations. With the advent of radar technology during World War 2, however, astronomy took a great leap outward. With radio antennas pointing to the night sky, astronomers far -----23-------------------their reach.

  1. with which

  2. from which

  3. by whom

  4. for which
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

We use 'with' for tools and 'by' for persons. The third option is 'by whom' and it's used for living things.

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