此前已有研究表明红茶对心血管健康也有好处。
Other studies have shown that black tea also has benefits for cardiovascular health.
此前已有研究表明，女性是否给孩子母乳喂养跟她们的年龄和教育背景有关。
Previous research has shown that age and educational background are linked to breastfeeding figures.
然而，研究文献业已表明，有效性概念已有不同含义。
But researches have shown that validity concept have had different meanings.
已有研究结果表明金融市场波动过程具有显著的长期记忆性。
Previous studies indicate that the volatility process of financial market has a distinctive long memory.
已有研究结果表明金融市场波动过程具有显著的长期记忆性。
Previous studies indicate that the volatility process of financial market has a distinctive long memory.
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