Question

I shall have completed this work by the time you returned from your trip
Find out erroneous part above sentence

Answer 1

Answer:

I should have completed this work by the time you returned from your trip.

Answer 2

‘You returned from your trip’ is the erroneous part of the sentence.

EXPLANATION:

In the above sentence the speaker wants to convey a message that the speaker would complete his work by the time the listener returned from his trip. So there is a sense of future being referred in this sentence. However in the given sentence the word returned has been used which denotes the past tense.  

This is what makes this sentence and erroneous sentence. The correct answer would be I shall have completed this work by the time you return from the trip.