Multiple choice

Directions: Fill in the blank with appropriate option.

The Chernobyl tragedy had taken place about four years _______

  1. past

  2. ago

  3. before

  4. since

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The word 'ago' is used to indicate a time measured back from the present. 'Before' usually requires a reference point in the past.