I. 1. different 2. for 3. since 4. How long ( ko chắc) 5. go II. 1. to cook 2. traveling 3. written 4. going 5. have worked 6. clean 7. hasn't written 8. go III. 1. He hasn't seen her for 5 years ( ko chắc) 3. He is as tall as Lan 4. He isn't strong enough to lift a heavy box.
