GRAMMAR MODALS AND SEMI-MODALS + VERBS SUBSTITUTING MODALS 13 Choose the correct option. 1. You are able to/can/need to click on the send button if you want to submit your registration form to WWF. 2. Did you have to/Had you to/Needed you to interview the boy who, at 15, had already planted 15 billion trees? 3. They can t have entered/couldn t to enter/weren t allowed enter the national park: it was undergoing massive changes and it was closed to the public! 4. Correct and ecological sewage is one of the topics we can/should/must bring our attention to: it s imperative. 5. They didn t need to think/ought to have thought/needn t have thought about poisonous precipitation before planting those delicate flowers in this area. 6. According to the report, wind and water can has been/need have been/must have been the main agents of soil erosion in this area. 7. We should/can/have use more detergents that are paraben and silicon free. 8. Shall/Would/Should you please refrain from dumping your waste out of the designated zones? 14 Say if the verbs in italics in these sentences are correct ( ). If not ( ), correct them. 1. Because of this year s acid rain, we may lose all our crops. 2. Nature s balance must never to be disturbed too much. 3. Though there were plenty of people, we were able hear the environmentalist clearly. 4. If he had chopped down all that wood, he could has been fined by the Regional Park Committee. 5. We needn t have purified that water: it had already been filtered and verified by the central authority. 6. The introduction of cloned plants and OGMs must to affect evolution, there can t be a doubt about it. 7. They can t reduced their toxic waste unless they have stopped using those chemicals. 8. There ought be stricter laws to combat air pollution. 67 UNIT 6 B1+