Re-write the following sentences according to the instructions given after each. Make other changes that may be necessary, but do not change the meaning of each sentence.
If your friends get here before 7 o’clock we can take them out for dinner. (Re-write: Using 'unless')
Topic: Transformation — 'unless'
Answer
Unless your friends get here before 7 o’clock, we cannot take them out for dinner.
UNLESS means IF NOT, so converting from a positive "if" requires the MAIN CLAUSE to become negative: Original: IF they get here before 7, we CAN take them out. Unless: UNLESS they get here before 7, we CANNOT take them out.
Note where the negative goes. The condition clause stays POSITIVE ("unless your friends get here") and the negative attaches to the RESULT. Candidates frequently write "Unless your friends do not get here", which is a double negative meaning the opposite.
THE TEST: read your answer and ask whether it gives the same information as the original. Both versions must mean "dinner depends on them arriving before seven".
This transformation now appears in 2020, 2021, 2023, 2024, 2026 and here — six of the papers built so far. It is the most frequently examined transformation in this subject.