Sure, here is the conversation with the correct phrases filled in:

1. Tell me what's worrying you. What's **on your mind**?
2. I'm depending on you to help me tomorrow. I hope you don't **change your mind**.
3. You must decide soon. Come on, **make up your mind**.
4. This door is very loose. **Mind your head**.
5. It doesn't matter if you come late. It's OK. **I don't mind**.
6. I know what you're thinking. I can **read your mind**.

For the spelling: noun plurals section:

1. We send you our best **wishes** and many **kisses**.
2. He bought a dozen **boxes** of **matches**.
3. For Christmas he gave his sons **watches** and his daughters **dresses**.
4. The **boys** are doing very well in their **studies**.
5. She collects children's **toys** from different **countries**.
6. **Libraries** are usually closed on **Sundays**.
7. **Families** of **monkeys** have different **ways** of looking after their **babies**.
8. He has 30 cows, 65 pigs and over 80 **sheep**.
9. I often go to the river to see the birds and the **fish**.

For the second part of the noun plurals section:

1. Be careful, children. You'll hurt **yourselves** with those sharp **knives**.
2. Their **wives** waved their **handkerchiefs** until the train had disappeared from view.
3. Three people have recently lost their **lives**, falling from high **roofs**.
4. He bought two **kilos** of **tomatoes**.
5. Here are some **photos** of famous **heroes** of the Second World War.
6. **Women** can damage their **feet** by not wearing suitable shoes.
7. **Children** should brush their **teeth** twice a day.