The empirical study in the thesis adopted the involvement index, proposed by Hulstijn & Laufer, to explore the effectiveness of different learning tasks on incidental vocabulary acquisition.

• 人们认为对词汇的深入精确理解会加强其记忆。本文采用Hulstijn & Laufer 的专注量指数（involvement index），通过一项实证研究探讨了不同学习任务对于词汇附带习得的影响。