海水是取之不尽的化工原料资源库，从海水中可提取各种化工原料。下图是工业上对海水的几项综合利用的示意图：

（1）由MgCl₂·6H₂O晶体脱水制无水MgCl₂时，MgCl₂·6H₂O晶体在         气氛中加热脱水，该气体的作用是                                                                                                  

（2）电解无水MgCl₂所得的镁蒸气可以在下列      气体中冷却（选填代号）。

A  H₂   B  N₂    C  CO₂   D  O₂  

A client with a diagnosis of a bleeding gastric ulcer goes to the operating room for a partial gastrectomy. Postoperative nursing care would include

A．administering pain medications every 6 hours.

B．withholding fluids by mouth until the return of peristalsis.

C．positioning the client in high Fowler position.

D．flushing the nasogastric (NG) tube with sterile water.