If, however, an animal finds itself in abnormal conditions, it may show ____(不正常的) aggressiveness.
At the international level an ____(积聚) of hostile emotions finally finds expression in large-scale impersonal warfare.
It is not surprising if in these conditions people behave ____(好斗地) towards each other.
If, however, an animal finds itself in abnormal conditions, it may show abnormal ____(敌对的情绪).