It measured the changes by three indexes, namely, VP structural complexity, VP variation and VP structural accuracy, and compared the results with similar monologues by a group of native speakers.

• 结果显示：无论是总体样本还是不同起点组别，英语专业学生四年口语产出中所使用动词语法型式在复杂度、多样性、准确性等维度的变化方面均呈非线性模式。