English grammar error-spotting (clause control after copular ‘‘is’’): Read and choose the erroneous part; avoid redundant ‘‘that’’ with a finite clause plus modal ‘‘should’’ after a copular: ‘‘It does not matter how you do it; / what I want is that / you should finish the work within a month. / No error.’’

Given data

• A: ‘‘It does not matter how you do it;’’
• B: ‘‘what I want is that’’
• C: ‘‘you should finish the work within a month.’’
• D: ‘‘No error.’’

Concept / Approach
After the copular ‘‘is’’, the complement should be a bare content clause without an extra ‘‘that’’ introducing another finite clause with ‘‘should’’. The idiomatic choices are: ‘‘what I want is to finish…’’ (if same subject) or ‘‘what I want is that you finish …’’ (without ‘‘should’’ in many exam keys). Here, Part B triggers an awkward double subordination.

Step-by-Step evaluation
Part B is the source of awkwardness; the preferred correction is either (i) ‘‘what I want is that you finish the work within a month’’ or (ii) ‘‘what I want is for you to finish the work within a month.’’

Correction
Replace ‘‘what I want is that’’ with ‘‘what I want is’’; then write the complement appropriately: ‘‘… is that you finish …’’ or ‘‘… is for you to finish …’’

Common pitfalls

• Combining ‘‘is that’’ with ‘‘you should …’’ which many tests flag as redundant.

Final Answer
what I want is that