中国药典(2000年版)在进行酸碱性试验时，如未指明用何种指示剂时，均系指
A．甲基红B．甲基橙C．溴甲酚绿D．酚酞E．石蕊试纸
参考答案：E
—Do you often see John on the playground?
—No, but he is often seen the guitar in the park.
A. run; play B. running; to play C. run; to play
回收所用各部绞车、变向轮、千斤顶等设备，要严格按作业规程要求定位稳固，必须达到设备和信号的（）要求。
A.完好
B.灵敏
C.可靠
