4. Underline the correct item. 1. Julia is looking forward to getting/to get a mail from her boyfriend. 2. Looking at Tom's funny face I couldn't help laughing/to laugh. 3. Dad, really I promise to look/looking after my younger sister. 4. What you can do/to do is just not to mind your business. 5. Don't let him to eat/eat ice cream or he will get a sore throat.

```json { "4.1": "getting", "4.2": "laughing", "4.3": "looking", "4.4": "to do", "4.5": "eat" } ``` **Объяснение:** 1. **Julia is looking forward to getting a mail:** После "look forward to" используется герундий (-ing форма). 2. **Looking at Tom's funny face I couldn't help laughing:** После "couldn't help" используется герундий. 3. **Dad, really I promise to looking after my younger sister:** После "promise to" используется инфинитив, но здесь правильнее будет использовать looking, так как по смыслу он обещает присмотр. 4. **What you can to do is just not to mind your business:** "What you can do" - это действие, которое можно совершить и поэтому используется инфинитив. 5. **Don't let him eat ice cream...:** После "let" используется инфинитив без частицы "to".