分类法是现代生物学研究的重要方法。[ ]
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My pencil-box is better than _____. [ ]
A. his and her
B. he and she
C. his and hers
D. him and her
精馏塔的进料状态有几种?他们对精馏段及提馏段的下降液体流量及上升蒸汽流 量有什么影响?