If I do... and If I did

This lesson explains the difference between 'If I do...' and 'If I did'. Both start conditional clauses but they signal different meanings and time frames.

• 'If I do...' uses the present simple in the if-clause. It describes real or possible situations in the future (first conditional) or general truths.
• 'If I did...' uses the past simple in the if-clause. It often expresses hypothetical or unreal situations (second conditional) or refers to past actions in conditional sentences.
• Choose the correct verb form depending on whether the situation is likely/real (use 'do') or hypothetical/unreal (use 'did').

Decide whether the condition is likely or hypothetical:

• Use 'If I do...' (present) for real, possible future actions: If + present, will/can/must + base verb.
• Use 'If I did...' (past simple) for unlikely or imaginary present/future situations: If + past, would/could/might + base verb.
• If you're talking about a past condition that actually happened, use past forms or past perfect as needed.

Think: 'do' = possible/real, 'did' = hypothetical/unreal

Watch out for these universal learner errors when using conditional sentences:

• Mixing tenses: using past simple ('did') in the if-clause but using 'will' in the result clause (incorrect pairing).
• Using 'would' in the if-clause (e.g., 'If I would go...') — 'would' belongs in the main clause, not the if-clause.
• Incorrect word order in questions formed with conditionals.
• Forgetting that zero and first conditional use present simple in the if-clause; second conditional uses past simple in the if-clause.

Always check both clauses: the if-clause and the main clause must match the intended meaning (real vs hypothetical).