过敏

例句：

1. 1. She has an allergy to cats, so she avoids them at all times.
   她对猫过敏，所以时刻避免接触。
2. 2. The doctor prescribed an antihistamine for her allergies.
   医生给她开了抗组胺药来治疗她的过敏症。
3. 3. Allergies can cause severe symptoms like hives and difficulty breathing.
   过敏可以导致严重的症状，如荨麻疹和呼吸困难。