单选题 When you are invited, you are supposed to be punctual.
  • A. in time
  • B. on time
  • C. polite
  • D. courteous


【正确答案】 B
【答案解析】[解析] be punctual等于be on time，守时、准时；in time：及时；couscous和polite表示礼貌。