试题题干
Fill in each of the following blanks with a word or an expression.
All transformational rules perform three kinds of operations: 
the sentence elements; adding a new element to the phrase marker; deleting an element from the phrase marker.
参考答案
试题解析
所有转换规则都执行三种操作：重新排列句子元素；向短语标记添加新元素；从短语标记中删除元素。