核内中子数为N的R²⁺ 离子，质量数为A，则ng该氧化物中所含电子的物质的量                                                                   [ ]

A．                  

B．      

C．(A-N＋2)mol                    

D． 

You want to use the Web to let (76) users or your customers look (77) corporate information. But you want to keep installation at the user end (78) and you don’t want just. (79) to get (80) your databases. That may be where an application server enters the picture. For more user machine independent, these software packages, typically written in the (81) programming language for use on Windows (82) -based systems, act as go-betweens (83) browser-equipped end users to the databases that (84) the information they need to (85) .

A．at

B．by

C．in

D．out