Summary of "Transformation of Sentences | ICSE & ISC Grammar | Rules | Boards 2026"

Transforming conditional sentences

Topic: If → Unless; If (third conditional) → But for Speaker: Arin Takar (Arin Tutorials, YouTube)

Core idea: “unless” = “if … not.” Use “unless” to replace an if-clause that contains negation, or to express the negative condition in an equivalent form.
Comma rule: When the sentence begins with an unless-clause, place a comma after that clause.
Subject–verb agreement: After replacing, ensure the verb form and agreement remain correct (e.g., “does not complete” → “completes”).

Conversion patterns and examples:

If + not (negative if-clause) → replace “if … not” with “unless …” and keep the main clause as is.
- Formula: If NOT A, B. → Unless A, B.
- Example: If you do not follow the safety rules, you will get hurt. → Unless you follow the safety rules, you will get hurt.
If (positive) → Unless (positive) but negate the main clause to keep equivalence.
- Formula: If A, B. → Unless A, not B.
- Example: If you water the plants regularly, they will remain healthy. → Unless you water the plants regularly, they will not remain healthy.
If NOT A, NOT B → becomes Unless A, NOT B (double-negative case simplified)
- Formula: If NOT A, NOT B. → Unless A, NOT B.
- Example: If you do not follow your instincts, you will not lead to the right destination. → Unless you follow your instincts, you will not lead to the right destination.

Example transformations shown in the video:

If she does not complete the assignment, she will lose marks. → Unless she completes the assignment, she will lose marks.
If I do not get enough rest, I will not be able to accompany you. → Unless I get enough rest, I will not be able to accompany you.

Core idea: Replace third-conditional negation (“If [someone] had not done X, Y would have happened”) with “But for + (noun/pronoun + noun phrase/gerund)” to express the same meaning.
Structure: But for + (noun/pronoun + noun/gerund phrase), result clause (would/could/might + have + past participle).

Conversion pattern and examples:

Pattern: If + past perfect (had + past participle), would have + past participle → But for + (noun/pronoun + noun phrase), would have + past participle.
- Example: If she had not reminded me, I would have missed the meeting. → But for her reminder, I would have missed the meeting.
- If they had not rescued the puppy, it would have died. → But for their rescue, the puppy would have died.
- If she had not studied consistently, she would have failed the test. → But for her consistent study, she would have failed the test.
- If the doctor had not arrived on time, the patient would not have survived. → But for the doctor’s arrival on time, the patient would not have survived.

Keep the meaning equivalent: sometimes you must negate the main clause when replacing If with Unless.
Watch grammar after conversion (verb forms and subject–verb agreement).
Place a comma after an initial unless-clause.