① Now, in Austin, there were nightmares. ② I would dream either of friends being shot dead, or see pools of blood spilling from bullet-riddled bodies, or that I myself was the target of gunfire. ③ I would wake up in a sweat, terrified of going back to sleep. ④ During the day, the sound of police or ambulance sirens made me jumpy. ⑤ Helicopters flying overhead made me uneasy. ⑥ I had to constantly remind myself that these were most often civilian and not military helicopters. ⑦ I had to remind myself that the ambulances were not rushing to evacuate wounded demonstrators.

1. What is the paragraph mainly about?
　
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2. How are the first three sentences coherent with each other?
　
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3. Sentences ④ and ⑤ shift to describe the real situation around the author. How do they maintain the coherence?
　
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4. What are the subjects of sentences ②, ③, ⑥and ⑦, and do they help to build up coherence of the text?
　
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5. How many groups of parallel sentence patterns can you find in the paragraph? Why are they used?
　
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