问题
                    
Must I return the book this week — No, you ____. You can _ it for 20 days.
                            A:mustn't: keep
B:needn't; borrow
C:needn't; keep
D:mustn't; borrow;
                        
                        B:needn't; borrow
C:needn't; keep
D:mustn't; borrow;
正确答案是:
                        