—My father has decided to________ smoking.  

—That's good news for us. I hope so.   [ ]

A. give up                

B. take out    

C. give in                  

D. turn off

Na₂O、NaOH、Na₂CO₃、NaCl、Na₂SO4可按某种标准划为同一类物质，下列分类标准正确的是                          （   ）

①钠的化合物                                                ②能与硝酸反应的物质；

③可溶于水的物质；                                      ④电解质；

⑤钠盐；                                                       ⑥钠的含氧化化合物

A．①③④⑤

B．①②⑤⑥

C．②⑤⑥

D．①③④