Unit 5 课时作业15-【红对勾讲与练】2022-2023学年新教材高中英语必修第一册(外研版)

Unit 5　Into the wild　　　　　　　 课时作业 15 　 　 　 　 　 　 　 　 　 　 　Ⅰ. 完形填空 Some of the greatest problems we face today are concerned with the gradual destruction (破坏) of our environment through overuse of our　 1 　 . So my family do what we can. We take cloth bags to stores instead of using plastic bags. We walk where we don􀆳t have to　 2　 . But when I􀆳m the only one with a cloth bag in line at the grocery store, I ask myself: Does it do any good? I recently found the answer from flamingos (火烈鸟) . These beautiful birds gather in　 3　 groups of a thousand or more. Every year, when the time comes for migration (迁徙), a few flamingos start the process by 　 4 　 from the lake. But　 5　 of the others seem to notice, so the tiny group returns. However, the next day they 　 6 　 again. This time a few more struggle along with them, but the vast majority 　 7 　 no attention, so these pioneers come back. The trend continues for several more days. Every time a few more birds join in but, 　 8　 the thousands of others still take no notice, the great migration plan is once again　 9　 . Then one day, things 　 10 　 . The same small group of birds takes wing and a tiny number more join in, just as before. This time their total number is enough to tip the balance (扭转局势) . The whole group takes flight and the migration　 11　 . A few can make a　 12　 . It􀆳s true that all of the great problems of the world have been solved because of the　 13　 efforts of a few. If you believe in a cause, don􀆳t 　 14 　 . Others will someday notice and 　 15 　 we