问题
                    
A: I’m going on a trip to Singapore after the exam.B: Really ______!
                            A:When , has left
B:When , has been away
C:How long , has left
D:How long , has been away;
                        
                        B:When , has been away
C:How long , has left
D:How long , has been away;
正确答案是:
                        