【简答题】Read the letter below carefully and fill in the blanks with right answers. 仔细阅读下面邀请函,补充正确信息。 December 16.2012 Dear Jessica, I am hoping that you can ______ (参加) the ______ (圣诞晚会) on the evening of ___...
【单选题】已知某疾病患者8人的潜伏期(天)分别为:6,4,9,12,10,7,13,>20,其潜伏期的平均水平约为()