-Did your parents learn English?    

-____________.They spoke well.    [ ]

A. Yes,he did    

B.No,they don't  

C.Yes,they did

写出下列物质或微粒的电子式(每空1分)

(1) CaCl₂               (2)CO₂              (3) KOH          

(4) HF             (5) Na₂O₂               (6) N₂             

(7) 镁离子    (8)硫离子     (9)NH₄Cl_________ (10) Cl_{2____________________}