IV
1. were watching
2. haven't been cleaned
3. Are they practising
4. to change
V
1. misunderstood
2. inventor
3. famous
4. gradually
VI
1. A of
be full of : đầy
2. B events
3. C experience
4. D where
VII
1. The shortage of clean water is one of the most urgent environmental problems
2. 1300
3. Massive volumes of industrial effluent which pour into the lake every day
4. No, they don't
VIII
1. they didn't want to send their son to a university in the USA
2. was designed by that well-known architect last year
3. is less hard-working than Tom
4. you follow your teacher's advice, you'll fail the final test
