What caused the blackout in July 1977?
- A During a storm, lightning damaged cable.
- B Because of unemployment.
- C Heat waves had made people use too much electrical power.
- D Because the looters damaged the electricity supply.
问题
What caused the blackout in July 1977?
参考解析：
34．答案为A 根据最后一段...when lightning hit andknocked out supply cables可知停电是由于闪电击中了供电电缆。
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