题目

实验室配制一定溶质质量分数的氯化钠溶液时，下列操作会导致结果偏小的是(    ) ①称量的氯化钠固体中含有不溶性杂质;   ②用量筒量取水时仰视读数; ③往烧杯中加水时有水洒出;④将配制好的溶液装入试剂瓶中时有少量溅出。 A．①②                      B．①③                      C．②④                      D．③④ A cat in London has been taking a bus regularly. The driver even knows where to _______ this special passenger. A. put down                                                    B. pick out C. leave behind                                                 D. drop out