试题题干
The constituents which must be present on the right side of the arrow in a phrase structure rule are called （ ）constituents.
参考答案
正确答案：
试题解析
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。
The constituents which must be present on the right side of the arrow in a phrase structure rule are called （ ）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。