题目

They were walking along the path when a blue flower______. A．came into sight           B．be in sight C．lose sight of              D．was out of sight 答案：A[2016上海]能证明乙酸是弱酸的实验事实是A．CH3COOH溶液与Zn反应放出H2B．0.1 mol/L CH3COONa溶液的pH大于7C．CH3COOH溶液与NaCO3反应生成CO2D．0.1 mol/L CH3COOH溶液可使紫色石蕊变红