一个长方体至少有( )条棱长度相等,最多有( )条棱长度相等。
4;8
用所给单词的适当形式填空。
1. I like watching TV and ______ (play) tennis.
2. My sister often plays tennis with ______ (she).
3. Her favorite ______ (subject) in school are music and P.E.
4. Kate's parents ______ (not) like playing computer games.
5. Could you tell me something about ______ (you), Jack?
实体完整性规则规定:关系中的元组在组成______的属性上不能为空值。