Read the passage given below and answer the questions that follow. Yet as soon as she saw him, she did not look as Alfred thought she would look : she smiled, her blue eyes never wavered, and with a calmness and dignity that made them forget that her clothes seemed to have been thrown on her, she put out her hand to Mr. Carr and said politely, "I'm Mrs. Higgins. I'm Alfred's mother." Mr. Carr was a bit embarrassed by her lack of terror and her simplicity and he hardly knew what to say to her, so she asked, "Is Alfred in trouble?" "He is. He's been taking things from the store. I caught him red-handed. Little things like compacts and toothpaste and lipsticks. Stuff he can sell easily," the proprietor said. Mrs. Higgins put out her hand and touched Sam Carr's arm with an understanding gentleness, and speaking as though afraid of disturbing him, she said, "If you would only listen to me before doing anything". Her simple earnestness made her shy; her humility made her falter and look away, but in a moment she was smiling gravely again and she said with a kind of patient dignity, "What do you intend to do, Mr. Carr?" "I am going to get a cop. That's what I ought to do." "Yes, I suppose so. It's not for me to say, because he's my son. Yet I sometimes think a little good advice is the best thing for a boy when he is at a certain period in his life," she said. Alfred couldn't understand his mother's quiet composure, for if they had been at home and someone had suggested that he was going to be arrested, he knew she would be in a rage and would cry out against him. '... he hardly knew what to say to her.' The underlined is a/an __ clause.