“Cost，Insurance and Freight”means that the seller delivers when the goods pass (1) in the port of shipment．The seller must pay the costs and (2) necessary to bring the goods to the named port of destination．But the risks of loss of or damage to the goods，as well as any additional costs due to events occurring after the time of delivery，are transferred from the seller to the buyer．However，in CIFthe (3) also has to procure insurance against the buyer’s risk of loss of or damage to the goods during the carriage．Consequently，the seller contracts for insurance and pays the (5) ．The CIF term requires the seller to (5) the goods for export．

A．buyer

B．seller

C．freight forwarder

D．carrier

某化学课外活动小组在实验室设计了如下图所示的实验装置，进行“氨的催化氧化”实验。

（1）A处是气体发生装置，A中所用的试剂只能从下列物质中选取： ①硝酸铵；②碳酸铵；③碳酸氢铵；④氯化铵；⑤熟石灰；⑥氢氧化钠。若A中制取气体时只用了一种药品，则该药品可以是_______________（填选项编号），在只用一种药品制取氨气时，图中空白处所需仪器应为____________________（选填下列仪器编号，固定装置省略）。

（2）该装置补充完整后，仍然存在一定缺陷，试从安全与环保的角度来考虑，对该装置进行改进：

①_______________________________________；

②_______________________________________。

（3）按照改进后的装置进行实验，请完成以下问题：

①装置B的作用__________________________________________________________；

②写出C中发生反应的化学方程式：_________________________________________；

③若A、B处试剂足量，则装置D中可以观察到的实验现象有_____________________。