题目

Complete the sentences with the given words in their proper forms (用括号中所给单词的适当形式完成下列句子，每空格限填一词) 1. It is necessary for everyone to brush his. ________ after each meal. (tooth) 2. I have bought a new flat and it's on the ________floor of the building.(eight) 3. As middle school students, we should know how to look after________. (us) 4. The student missed the ________tour around Sheng Long Agricultural Park. (enjoy) 5. We received Peter's _______and went to his birthday party happily, (invite) 6. The serious fire _______ destroyed th的外接圆圆心为，半径为，为零向量，且.则在方向上的投影为A． B． C． D．