1. Their daily work is to refine crude oil. ����ÿ��Ĺ����Ǿ���ԭ�͡�
2. They refine sugar using this way. ���������ַ��������ǡ�
3. But first, they must refine its motor skills. �����ȣ����DZ���������˶����ܡ�
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v.
1. improve or perfect by pruning or polishing
2. make more complex, intricate, or richer
3. treat or prepare so as to put in a usable condition
4. reduce to a fine, unmixed, or pure state; separate from extraneous matter or cleanse from impurities
5. attenuate or reduce in vigor, strength, or validity by polishing or purifying
6. make more precise or increase the discriminatory powers of