题目

Read the passage and fill in the blanks. (首字母填空)Eating out is one of the joy of being in the USA. The food is usually good and often excellent; the p【1】 are reasonable; and the service is mostly fine. Some restaurants are o【2】 for breakfast; others are open twenty-four hours a day. A number of restaurants call themselves family restaurants. Many of these serve no alcohol and all are at very reasonable prices. Many restaurants, especially the more expensive ones, open at about 11：30a.m. It is the most n【3】 time for lunch in the USA, and some remain open until the evening一个质量为2kg的物体，以4m/s的速度在光滑水平面上向左滑行，从某时刻起在物体上作用一个水平向右的水平力，经过一段时间，物体的速度方向变为向右，大小仍是4m/s，在这段时间内水平力对物体所做的功为（　　）A．0JB．3JC．16JD．32J