Смодальными глаголами 1. high intensity of human activities be the cause of water pollution a) is able b) may c) ought d) should 2. lanfills are needed for waste that be recycled or safely burned a) can't b) needn't c) mustn't d) should not 3. efforts to decrease air pollution be made at the national as well as at international levels a)are able b) have c) must d) ought 4. manufacturers make products that have fewer toxic components a) are able b) need c) ought d) should 5. an effective sewage discharge technology be used to control water quality a) should b) need c) is able d) has 6. any large engineering projects harm the earth or the life on it a) can't b) might not c) mustn't d) needn't