试题题干
Judge whether each of the following statements is true or false. Write T for true or F for false in the blank offered after each statement.
The constituent which may be present or absent on the right side of the arrow in a PS rule is called a compulsory constituent.
参考答案
正确答案：
试题解析
The constituents which must be present on the right side of the arrow are called compulsory constituents.
在短语结构规则中，必须出现在箭头右侧的成分称为强制成分。