Select the alternative that will improve the underlined part of the sentence, in case there is no improvement, select "No Improvement".

They didn't complain lest they will annoy the neighbours.

The correct alternative to improve the underlined part is 'lest they should annoy'.

Key Points

• The conjunction 'lest' means 'for fear that or in order to avoid'. It is followed by something the speaker thinks should be avoided.  
• When the subordinate clause follows 'lest,' the auxiliary verb 'should' is used regardless of the tense of the verb in the main clause.
• Examples, 
  • We start early lest we should miss the train.
  • Speak quietly lest she should hear us.
• According to the usage and examples that are given above, 'should' is used instead of 'will'. 
• Therefore, option 1 is the correct answer.