5 Complete the sentences with the words in Exercise 4. Write the answers in your notebook 1 Some people say that in 20 years people will not have the opportunity to see gorillas. These animals are ? , so if they are not protected, they will die out. 2 Scientists say that ? is the key factor to solve the world's environmental problems. 3 Don't touch that bottle. It has ? liquid inside which is harmful to people. 4 Our shop has a box full of ? shopping bags. Customers can take them for free and use them. 5 This park is a safe area for all animals. No one can harm them here because they are ?
