Directions: Complete the following passage by using ONE word that fits the context.
Because neither she nor her husband smoked, Mrs. Trench was surprised to see cigarette ash on her doorstep as she entered the house. When she opened the living-room door, she was astonished to see a strange man fast 48 in an armchair! Taking care not to disturb him, Mrs. Trench left the house at once. She called a taxi and went 49 to the police station. When she got there, she lost no time to explain _____50 had happened and added that the man 51 have got into the house 52 an open window. Mrs. Trench returned home 53 a police car together with two policemen. But it was too late: the man had disappeared. Hurrying upstairs, she went to her dressing-table. She smiled 54 relief when she saw the only thing that man had taken was an imitation diamond necklace that was almost 55 !