题目

The servant did _____ she could ______ the revolutionary. A. what, help  B. that, to help C. what, to helpD. all help   答案：Cdo what one can to do sth. = do all that one can to do sth.不定式表示目的。下列用于鉴定蛋白质的试剂及其颜色反应是 A．苏丹Ⅲ染液，橘黄色            B．斐林试剂，砖红色 C．碘液，蓝色                    D．双缩脲试剂，紫色