Ellipsis

What is ellipsis? It allows you to omit repeated subjects, verbs, or phrases under certain conditions. It is recommended to use auxiliary verbs (do/does/did) to reduce repetition in the second clause.

Remove repeated subject

• He closed the door and he took off his shoes.
• We could go out or we could have a party at home.
• She called but she didn’t leave a message.

Repeat only auxiliary or modal verb

• Maria should take the exam, but I don’t think you should take the exam.
• She’ll go to the meeting but I won’t go to the meeting.
• They say he is the best right now, but I don’t think he is the best.
• She doesn’t like it, but I do.
• She liked it, but I didn’t.

Reduced Infinitive

• I shouldn’t go out tonight, but I really want to go out.
• Are you going to sell the car?’ ‘No, I‘ve decided not to sell the car.

References

• Ellipsis and substitution - Test-English