This article introduces a limit testing on large models, which significantly improves the performance of GPT-4 and Claude2.1 by adding specific prompt statements at the beginning of the responses. The test results show that large models have difficulties in finding specific sentences, but this method can address the issue. In addition, the Kimi team from the Dark Side of the Moon also proposes different solutions and achieves good results. The entire experiment demonstrates that the performance of large models is subject to certain limitations, but it can be improved by appropriate prompts and adjustments.