English grammar error-spotting (word form ‘‘economise/economize’’ and conditional harmony): ‘‘I am sure that all my monthly expenses / would exceed the income / If I do not economic / No error.’’ Identify the erroneous part.

Concept / Approach
‘‘economic’’ is an adjective; the required verb is ‘‘economise/economize’’. Also, for a real present/future condition the apodosis normally uses ‘‘will’’ rather than ‘‘would’’.

Primary correction (tested error)
‘‘… if I do not economise.’’

Full polished version (style)
‘‘I am sure that all my monthly expenses will exceed my income if I do not economise.’’

Common pitfalls

• Using an adjective where a verb is required.
• Mismatching conditional tense harmony (would … if I do …).

Final Answer
If I do not economic