[单项选择]选用乙醇作药材浸提溶剂时,下列表述中错误的是 A. 乙醇浓度20%以上时具有防腐作用 B. 乙醇浓度大于20%时,能延缓酯类、苷类等成分水解 C. 乙醇浓度50%以下时,适于浸提苦味质、蒽醌苷类等 D. 乙醇浓度50%~70%时,适于浸提生物碱、苷类等 E. 乙醇浓度90%以上时,适于浸提挥发油、有机酸、树脂等
第6题: [单项选择]When will the library be open on Saturday A. From 8 a.m. to 5 p.m.. B. From 8 a.m. to 9 p.m.. C. From 5 a.m. to 9 p.m.. D. From 9 a.m. to 5 p.m.. 参考答案:D 答案解析:[听力原文] W: I certainly hope the library will be open this Saturday. M: The sign says library ho
第15题: [单项选择]Before you decide on a vocation, it might be a good idea to consult a few good friends. A. career B. holiday C. plan D. research 参考答案:A 答案解析:career事业、职业;holiday节日;plan计划;research研究。因为vocation意为“职业”,故选A项。注意:不要将vocation与vacation(假日)混淆。