warmer is not necessarily related to the subject of the lesson. also this step is normally doe by greeting and checking the homework as well. on the other hand,Lead-in is always related to the subject of the lesson. for example for teaching the language target of this session, teacher can ask Ss to discus about the experience of visiting a doctor or dealing with different health problems in different situations.

Exposure gives the Ss the chance to acquire language. Moreover, the students will be already familiar with the content before the teacher focuses on the grammar or vocabulary. This lesson includes a conversation between a mother and her daughter on visiting a doctor in which `must` is used as a way of showing obligation and logical conclusion.

in this lesson Ss are asked to find different examples of `must` from the conversation they heard.

in this step the differences of `must` in obligation and logical conclusion will be clarified by asking proper questions, giving example with options and also including information gap.

controlled practice is done by trying to provide proper contexts that make Ss to use new language. For instance by asking for the rules they have to obey in order to practice obligation and trying to present deduction for practicing logical conclusion.

Ss in pair work or group work discus language target and report the idea of their peer(s).

this part is presented by a discussion on a specific subject that Ss are allowed to use their previous knowledge and target language.