归纳、分类是学习化学的重要方法．请根据化学式的意义从H₂、P₂O₅、0₂、NO₂、Fe、O₃六种物质中选出部分物质归为一类，回答下列问题：

（1）选出的一组物质的化学式有                      

（2）分类的依据是                                 ．

I thought the plan he____at the meeting____.    [ ]

A. put on;makes no sense            

B. put forward; made no sense    

C. put off;didn't make any sense    

D. put forward;doesn't make ariy sense