样品mg $\frac{H_{2}O}{溶解}$ 溶液 $\frac{过量氯化钡溶液}{过滤}$ 沉淀 $\frac{水}{洗涤}\frac{低温烘干、冷却、称量}{}$ 固体ng

①如何检验氯化钡溶液已过量____；

②检验沉淀是否洗涤干净所用到的试剂是____；样品中NaCl的质量分数的数学表达式为____．

要在显微镜下观察到完整的半月形的保卫细胞和气孔，所需要的玻片标本为（　　）

                                                                             House of Porridge                                                                                                               
   Welcome to Clark’s Porridge House. We have different kindsof porridge. We have meat porridge, vegetable porridge, and fruit                porridge is our special. It is only RMB 4 for one bowl. A bowlof meat porridge is RMB 5.Vegtable porridge is RMB 3 for one
bowl, but RMB 5 for two. We have thin pancakes, too. They are RMB5for ten. Come and taste delicious the food here. If you are too
busy to come, call us and we can deliver the food to you in20 minutes.

Fill in the blanks according to the passage Only one word for each blank
   The owner of this porridge house is (1)____ . The cheapestis the (2)____ porridge. If you eat a bowl of meat porridge and  five thin pancakes, you will pay RMB(3)____ . (You can explainit either in Chinese or in English.) The word“deliver”in the last sentences probably means(4)____ . If you order some goodin this restaurant at 6 o’clock, you will probably get it before(5)____ .