临床试验中所有观察结果和发现都加以核实，以保证数据的可靠性的是
A．质量保证B．多中心试验C．试验方案D．记录与报告E．试验用药品
参考答案：A
Check carrots，potatoes, onions and any other vegetables_____ and immediately use or throw away any which show signs of rotting.
A．in demand
B．in store
C．on loan
D．on sale
试分别概述南北朝民歌的思想内容？
