点击下方单词,选择对的这个单词
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1. the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
e.g. the fall broke his back
Synonym: spinal columnvertebral columnspinebackboneback
2. axis of a compound leaf or compound inflorescence
多通过句子记忆单词，而不是单独死记硬背。
