Before revision: Deep learning has been widely adopted in natural language processing applicationsin recent years. Many existing studies show the vulnerabilities of machine learning and deep learning modelsagainst adversarial examples . {\em   However, most existing works currently focus on evasion attack on text data instead of positioning attack , also named backdoor attack .
After revision: Recently, advanced NLP models have seen a surge in the usage of various applications . {\em However, most existing works currently focus on evasion attack on text data instead of positioning attack , also named backdoor attack .