The document discusses how to form yes/no questions in English. There are two main formulas:
1) For questions using the verb "to be", the formula is: Auxiliary verb + Subject + rest of the question.
2) For questions using simple tense verbs or modal auxiliaries, the formula is: Auxiliary verb + Subject + main verb in infinitive form + rest of the question.
When there is no auxiliary verb, "do/does/did" are used as auxiliaries before the subject. Modal auxiliaries like "can", "may", and "should" are also used to form questions and change the tense or meaning of the main verb.