单选题 The salesman approached the house cautiously when he saw the vicious dog at the door.
【正确答案】 C
【答案解析】[解析] cautiously意为“谨慎地,小心地”,如:She opened the door cautiously so as not to wake the baby.(她开门时小心翼翼,生怕吵醒婴儿。)其意义与C项carefully相同,故选项C正确。其他选项意义为:nervously“紧张地”,bravely“勇敢地”,deliberately“故意地”。