词汇推断题。由文中第三段“They did not lose any of the bombers they were escorting”可知，在第二次世界大战中，他们从未失去一架轰炸机的英勇战绩，而之后用but做转折，“But when they returned to America, they were appalled to find…”可知，当他们返回美国以后，却发现自己仍然受到不公平的待遇，前后反差，必然十分震惊，而四个选项中只有C项意思相近，故选C。shocked震惊的。reluctant不情愿的。pleased高兴的。relieved如释重负的。