Read the text again and complete the sentences with the correct beginning or ending

1. … based on the ability of a material to conduct electricity.

2. Conduction takes place as …

3. The ability of any material to conduct electricity …

4. … are called conductors.

5. Materials having very few (or no) free electrons …

6. Semiconductors are materials …

7. The terms “conductor” and “insulator” are not absolute, that is …

Work in pairs. Ask your partner questions based on the text. Make sure you use correct auxiliary verb.

1. Ways of classifying materials (How many?) …

2. The ability to conduct electricity (What?) …

3. As a result of (What?) …

4. Is directly proportional to (General question) …

5. Under normal conditions (Under what conditions?) …

6. Readily conduct electric current (How?) …

7. Such materials as selenium, silicon and germanium (How?) …

8. It should be realized (What?) …

24. Answer the following questions.

1. What is conduction?

2. What is conduction based on?

3. What groups are materials classified into according to their conductivity?

4. How does conductivity depend on temperature?

5. What materials are called: a) conductors, b) semiconductors, c) insulators?

SPEAKING