第3题: [单项选择]I can't keep ______ the teacher who speaks so fast. A. up B. up with C. with D. on with 参考答案:B 答案解析:[解析] 本题考查动词短语。keep up with“跟上”;keep up“维持,继续”;keep on with“继续 (做某事)”。句意为:我跟不上那位老师,因为他说得太快了。
第18题: [单项选择]铁盐检查法中,50ml溶液中所含待测杂质的适宜检测量为() A. 0.002mg B. 0.01~0.02mg C. 0.02~0.05mg D. 0.05~0.08mg E. 0.1~0.5mg 参考答案:C 答案解析:硫酸盐检查法中,50ml溶液中所含待测杂质的适宜检测量为0.1~0.5mg;铁盐检查法中,50ml溶液中所含待测杂质的适宜检测量为0.02~0.05mg;重金属检查法中,35ml溶液中所含待测杂质的适