The results show that passivevocabulary size progresses very well at the early stages of learning, but not at the later stage;
分析，得出以下结果：三个年级的被动词汇在不同的学习阶段都有不同程度的增长，但不是直线。
3
Researches into vocabulary knowledge measurement develop along three main lines, i. e. the passivevocabulary size, the depth of vocabulary knowledge and free active vocabulary.