the plural form of 'antrum', meaning '腔，窦' in Chinese (e.g., anatomical cavities or sinuses)
记忆技巧
Visual Association
Imagine an 'ant' (蚂蚁) crawling into a tiny 'cave' (洞窟). The word 'antra' sounds like 'ant' + 'ra' (like 'rah!'), so picture ants cheering as they explore multiple tiny caves (antra = cavities).
Breakdown & Rhyme
Split 'antra' into 'ant' + 'tra'. Think of a sci-fi 'ant transport' (ANT-TRA-nsporter) ship carrying ants through body cavities (antra).
例句
The doctor examined the patient's antra (sinuses) for signs of inflammation. (医生检查了患者的窦腔是否有炎症。)