Answer:
Here are the sentences with the underlined words changed into the plural form, along with any other necessary changes:
1. They were kind to me.
2. Are the babies hungry? Why are they crying?
3. They guided me to reach the schools.
4. I do my homework in the evenings.
5. They must solve the problems themselves.
6. I like the ways they speak English.
7. Be careful. You may hurt yourselves.
8. These books are mine. Where are hers?
9. You yourselves are responsible for the loss.
10. These toys do not belong to her. They are mine.