TheeffectofDarwinistideaof“survivalofthefittest”wasshatteringin()’sfictionalworldofjungle,where“killortobekilled”wasthelaw.
Onecanfigureoutthemeaningof“airmail”tobe“mailbyair”byits______.
英语翻译：comeintoforce
Idiomsnominalinnaturehavea(n)______asthekeywordineachandfunctionasanouninsentences.
不符合科技英语特点的是（）
