Identify the error in the sentence.
By the time they arrive, the concert had ended.
Show answer & explanation
Correct answer: B
Explanation
There is a mismatch between the present tense "arrive" and the past perfect tense "had ended.
To describe a completed past event, the action which ended earlier should be in past perfect tense and the action that ended later should be in simple past tense.
The sentence should be: "By the time they arrived, the concert had ended."