问题
                    
We often use QQ _____ e-mails.— Really Would you please show me _____
                            A:to send/ how to use it
B:sending/ what to use
C:send/ what can I use
D:to be sent/ why to use;
                        
                        B:sending/ what to use
C:send/ what can I use
D:to be sent/ why to use;
正确答案是:
                        