84. 　I think we all learned a _____________(宝贵的) lesson today.

83.　 She is studying American ____________ (文学)at Georgetown University at present.

82.　 Such b____________　 (行为)is unacceptable in public.

(注意：在答题纸上请写出完整的单词，不要忘写首字母。)

81.　 He is not a good doctor because he is short of e　　　　 (经验).