在下列各句的每个空格内填上一个适当的、完整的单词,该词的首字母已给。 1. He's unhappy because of his little dog's d__________. 2. The reason why he was away was not m__________ in the text. 3. We must keep the s between you and me. Don't let others know them. 4. Paris is one of the l__________ cities in Europe. 5. Students are often a__________ while having classes in the hot afternoon