改错A week ago,a post about Earth Hour put up on the notice board of our school,calling on us to turn

【专家解说】：答案是：A week ago,a post about Earth Hour (was )put up on the notice board of our school,calling on us to turn off all the lights for the(改为 an） hour from20:30to21:30. ☞ ♧手工翻译☀尊重劳动☀欢迎提问☀感谢采纳♧ ☜