问题
                    
________ she is not so cheerful ________ she used to be?
                            A:How it is that;as
B:How is it that;as
C:Is it why;that
D:Why is it that;what
                        
                        B:How is it that;as
C:Is it why;that
D:Why is it that;what
正确答案是:
                        