语法与词汇 The population bomb is a _____ that has already happened in some parts of the world, with terrible results.

【正确答案】 C

【答案解析】句意：人为炸弹爆炸事件是一种灾难，已经在世界的某些地方发生并造成了严重后果。distress悲痛；灾难。