问题
                    
They were_______ busy_______ with each other__________the time.
                            A:too; to talk; to forget
B:so; talking; that they forgot
C:so; to talk; that they forgot
D:too; talking; to forget;
                        
                        B:so; talking; that they forgot
C:so; to talk; that they forgot
D:too; talking; to forget;
正确答案是:
                        