Подчеркните в сложноподчиненных предложениях придаточные
предложения.

1. Substances can be divided into two classes: electrolytes whose solutions conduct
electricity and non-electrolytes whose solutions do not conduct electricity.
2. He would have used the device if it had been in order.
3. The University he studies at is one of the leading educational institutions in our
country.
4. The miscellaneous file contains documents which do not require a separate file.