Teaching in companies involves tremendous patience especially when one doesn't know the background if the students or where they would like to go with their English. The idea as I have said is not to get overly involved with the grammar especially if the object is for the person to converse in another language. I like to integrate grammatical pieces into reading/conversational exercises.
My formula for teaching an average class is that grammar makes up about a quarter of my time at most. After having found out what groups like most often I have the group read something. Last day it happened to be on favorite sport activities. The group came across three sorts of past-time activities: hiking, camping and skiing and read what each one entails. That would provide them with some information to back up any opinion on their likes or dislikes.
The individual would then answer questions on the activity of his choice from the reading and explain his reasons for doing it. Then he would ask his neighbor the same question and so on. The group would go through a list of questions asking each other in a circle. That way the group would have experienced how to ask and answer question on activities of their choice and learn to distinguish from one question and another. I would prompt one of the students to ask one of the others have said and that way get them to use reported speach. The student would then learn the difference between having reported what someone has said as opposed to asking directly.
Clearly this depends on the level that the group is in. If they are only beginners than the same question and answer period would best be done by having them practice questions on getting the identity of objects or getting the students to become aware of asking questions related to their own identity. That way the student would indirectly discover the value of changing interrogative words to change the type of question while understanding that the verb, to be, is used to ask about one's job or one's identity.
By deductive reasoning the people in the group eventually learn the difference between do and be in eliciting information and that do has to do with all sorts of activities where be is not present.
