问题补充：
单选题Somechildrenwereskatingontheicehappily.Suddenlyoneofthem____thewaterandtheotherchildrenfelt____.A.falls into; frighteningB.fell into; frightenedC.fall into; frighteningD.fall into; frightened
答案：
B解析此题考查动词短语fall into表示掉入…里面，因发生在过去故用过去式fell；frightened和frightening都可做形容词，但前者常用来修饰人，后者常用来修饰物，故选B。
