Research on Possible Causes and Solutions about the Problem of Second Language Vocabulary Acquisition Decay

English vocabulary learning is a difficult task for second language students. Therefore, it is very essential for second language students to master the methods of vocabulary memorization and how to prolong the time of vocabulary memorization. This paper will divide into three sections, namely describing a context with the problem of the accelerated lexical decay in a specific context in a Chinese after-school language class with details; analyzing possible causes and general solutions mentioned in vocabulary learning literature; as well summarizing what solutions to work in the specific after-school class in China.