（7分）“阿波罗号飞船”所用的氢氧燃料电池的电极应为：负极：2H₂＋4OH^－－4e^－＝4H₂O，则正极反应为                              ；该电池工作时,通氢气的一极发生                      反应（填氧化、还原），每转移4摩电子,电池内增加         摩水，负极附近溶液的PH值                ，（填升高、降低、不变），正极附近  [H+]    （填升高、降低、不变）

IP multicasting is a set of technologies that enable efficient delivery of data to many locations on a network. Rather than making multiple copies of a message intended to be distributed to multiple recipients at the (71) of origin of a message, multicasting initially sends just one (72) and does not copy it to the individual recipients until it reaches the closest common point on the network, thereby (73) the bandwidth consumed. Network performance is significantly (74) because it isn’t bogged down with the processing and transmission of several large data fries; each receiving computer doesn’t have to (75) the transmitting server for the file.

A．loop

B．find

C．search

D．query