I. 1. c - obstinate
2. 1) loyal - c верный
2) jealous - b ревнивый
3) inert - a вялый
4) talkative - d разговорчивый
3. 1) allow - c prohibit
2) protect - a hurt
3) catch - d throw
4) clean - b pollute
4. c
II
1. My sister doesn't like coffee.
2. Water is a vital element of life.
3. If people thought more about their future, they would never pollute the rivers.
4. You should stop eating sweets.