1. Do not → Don't
Ex - I don't like spiders.

2. Had not → Hadn't
Ex - He hadn't been told.

3. Has not → Hasn't
Ex - She hasn't left.

4. Is not → Isn't
Ex - This isn't difficult.

5. Must not → Mustn't
Ex - I musn't make a noise.

6. Need not → Needn't
Ex - You needn't come.