Here are possible words to fill in the blanks:

11. **ECONOMY**
a. We're spending too much. We must **economize**.
b. This car uses a lot of petrol. It’s terribly **inefficient**.
c. The Chancellor (Minister of Finance) is responsible for **economic** affairs.

12. **RESIDE**
a. This is the President’s official **residence**.
b. There’s no industry or entertainment here. It’s a **residential** district.
c. **All** of the neighboring houses were warned of the gas leak.

13. **COMFORT**
a. In that tense situation, I found the good news very **comforting**.
b. I felt rather **uncomfortable**, so I put a soft cushion behind me.
c. She sat in terrible **comfort** on the hard chair for over an hour.

14. **DEAD**
a. The increasing number of **deaths** in traffic accidents is alarming.
b. Be careful! That’s a **deadly** poison!
c. The doctor gave him an injection to **relieve** the pain.

15. **DEMONSTRATE**
a. The **demonstrators** marched through the streets chanting slogans.
b. Grandfather rarely showed the affection he felt for his family. He was a very **demonstrative** person.
c. What you say is **demonstrably** false. Let me show you the facts.

16. **IMITATE**
a. The bag is made of **imitation** leather.
b. Small children are very **imitative** in their behavior. They just copy what they see.
c. His acting style is **imitable**. No one can copy him.

17. **ARGUE**
a. She had an **argument** with her husband last night.
b. He’s a very bad-tempered, **argumentative** chap. He’s always quarrelling.
c. She is the finest pianist in the world.