Don't assume that your class textbook has the language that your students need or want to learn.

Most textbooks follow a good syllabus and have some good activates and plans. They are certainly a useful tool for the teacher though if you use it exclusively then students will be bored. That’s why it’s important to bring your course book alive. See what grammar/function the book wants to cover and see if you can make a fun activity for it. It is the teacher's responsibility to add any extra necessary vocabulary, functions, grammar, or topics that you feel the students may want or need.