Based on your search query, I would recommend Grammarly for teaching Class 11 English grammar.

Grammarly is a comprehensive tool that checks for grammar, punctuation, and spelling mistakes, making it an excellent resource for teaching and learning English grammar. It also offers stylistic and best-practice writing suggestions, which can help students improve their writing skills and understand the nuances of English grammar.

The real-time comments and suggestions feature can be particularly useful in a classroom setting. As students write, they can receive immediate feedback on their work, helping them identify and correct mistakes on the spot. This feature can also help students understand why a particular sentence or phrase may be grammatically incorrect, enhancing their understanding of English grammar rules.

The plagiarism checker is another valuable feature for teachers. It can help ensure that students' work is original by scanning text for matches on the web and academic databases. This can be a great tool for teaching students about the importance of academic integrity and the consequences of plagiarism.

In conclusion, Grammarly offers a range of features that can effectively address your need for a tool to teach Class 11 English grammar.