Here's how you can complete the sentences with tag questions:

**Bài 4:**

1. I am making a big mistake, **aren't I?**
2. Let's go shopping at Saigon Coop Mart, **shall we?**
3. Children should drink a lot of milk and fruit juice, **shouldn't they?**
4. Bring your camera with you to the party, **won't you?**
5. These shoes need to be fixed, **don't they?**
6. You must ask for your parents' permission to join the trip, **mustn't you?**
7. Ba likes healthy food, **doesn't he?**
8. Thu didn't take part in the competition, **did she?**
9. Phong hasn't been to Hanoi before, **has he?**
10. She can ride to school by herself, **can't she?**

**Bài 5:**

1. We should follow the traffic rules strictly, **shouldn't we?**
2. He seldom visits you, **does he?**
3. You have never been in Italy, **have you?**
4. No one died in the accident, **did they?**
5. Nothing is wrong, **is it?**
6. Nobody called the phone, **did they?**
7. Everything is okay, **isn't it?**
8. Everyone took a rest, **didn't they?**
9. Going swimming in the summer is never boring, **is it?**
10. Let's dance together, **shall we?**

Feel free to adjust any phrases if needed!