第2题: [简答题]How should language rules be learned according to the Direct Method 参考答案:
Language rules are learned inductively through listening and speaking activities. The teacher sets up a few carefully chosen illustrations of a rule and leads the students to discover the relationship of the new elements to others previously learned and to formulate their observations into the rule governing those examples. In other words, students have to induce grammatical rules from examples in the text. A language could best learned by being used actively in the classroom.
第17题: [单项选择]在数据库三级模式结构中，外模式的个数( )。 A. 只有一个 B. 可以有任意多个 C. 与用户个数相同 D. 由设置的系统参数决定 参考答案:B 答案解析:[解析] 数据库的三级模式结构是指数据库系统的外模式、模式和内模式。外模式是与某一具体应用有的数据的逻辑表示，通常是模式的子集，一个数据库可以有多个外模式。
