完形填空。阅读下面短文，掌握其大意，然后从各题所给的四个选项（A、B、C和D）中选出最佳选项。
Do you remember last summer, when angry travelers were urging the government to do something about airline customer service? Airlines 1 to improve , and they adopted (采用)new standards just before Christmas. 2 as another summer nears, plenty of 3 travelers don’t see much improvement in customer 4 overall .
