American people divide their days into several blocks of time, and plan different activities （ 1 ） different times. American time is "on the dot"(准确地). If something is supposed to happen at eight o'clock, it willbegin at eight. Americans value promptness(准时)and may become angry if a person is more than 15 minutes late （ 2 ） a good reason. If you know you are going to be late, call in advance and let someone know. （ 3 ） you arrive late, you should apologize and explain why. Americans arrive （ 4 ） time for doctors' appointments. The doctor may keep you （ 5 ） , but if you keep the doctor waiting, you may get a bill with the doctor's time! 3、根据短文内容，在A、B、C、D、E五个选项中，选出最佳答案填入文中【3】处。（）.
A. for B. waiting C. on D. if E. without