First of all, we need to know what a grammatical error is. Grammatical errors refer to the violation of grammatical rules in language use. These errors may involve lexical, syntactic and semantic aspects. Common grammatical errors include subject-predicate agreement error, tense error, article error, preposition error and so on. For the grammatical mistakes in English graduation thesis, we can adopt the following methods to correct them.

First, check the subject-predicate consistency errors in the paper. Subject-predicate agreement error refers to the situation that the subject and predicate are inconsistent in person and number.

Secondly, check the temporal errors in the paper. Temporal errors refer to the use of incorrect tense forms when expressing time concepts such as past, present and future.

In addition, pay attention to the mistakes in the article. Article errors refer to problems when using indefinite article a/an or definite article the.

Finally, check the preposition errors in the paper. Preposition error refers to the use of incorrect prepositions when expressing time, place and reason.

When correcting grammar mistakes, graduates can use some tools to assist them, such as grammar checking software or paper duplicate checking system. These tools can quickly identify grammatical errors and give suggestions for modification. However, it should be noted that these tools are not perfect, and sometimes they are omitted or misjudged. Therefore, students also need to carefully check and correct themselves.