1. Have to
1.1. Used to express certainty, necessity, and obligation.
1.1.1. Affirmative: subject + have/has to + verb
1.1.1.1. I have to study for the exam
1.1.2. Question: Do/does + subject + have to + verb + ?
1.1.2.1. Does she have to study?
1.1.3. Negative: subject + don't/doesn't have to + verb
1.1.3.1. I don't have to study for the exam
2. Ought to
2.1. Used to advise or make recommendations.
2.1.1. Affirmative: subject + ought to + verb
2.1.1.1. You ought to stop smoking
2.1.2. Negative: subject + ought not/oughtn't + verb
2.1.2.1. You ought not smoke so much
2.1.3. Question: ought + subejct + verb + ?
2.1.3.1. Ought I stop smoking here?
3. Can
3.1. The verb 'Can' belongs to modal verbs and is located before the main verb in infinitive.
3.1.1. Affirmative: Subjet + Can + Verb
3.1.1.1. Mary can be very stubborn sometimes.
3.1.2. Negative: Subjet + Can not /Cannot/ Can't + Verb
3.1.2.1. You can't tell me what to do.
3.1.3. Interrogative: Can + Subjet + Verb
3.1.3.1. Can Peter speak German?
4. Could
4.1. Used to express ability in the past and to express politeness.
4.1.1. Affirmative: Subjet + Could + Verb
4.1.1.1. I could talk louder.
4.1.2. Negative: Subjet + Couldn't + Verb
4.1.2.1. I couldn’t talk louder.
4.1.3. Interrogative: Could + Subjet + Verb
4.1.3.1. Could you talk louder?
5. Might
5.1. The Might auxiliary verb is used to express possibility. It is a possibility or present or future, and the verb that follows is infinitive.
5.1.1. Affirmative: subject + might + verb
5.1.1.1. I might lose my job.
5.1.2. Negative: subject + might not + verb
5.1.2.1. We might not know everything.
5.1.3. Question: might + subejct + verb + ?
5.1.3.1. Might I give you a piece of advice?
5.1.4. Have: subject + might + have + participle
5.1.4.1. They might have arrived now
6. May
6.1. The verb 'MAY is used to express a certain degree of probability of an action or certainty:
6.1.1. Affirmative: subject + may + verb
6.1.1.1. You may ask three questions.
6.1.2. Negative: subject + may+ verb
6.1.2.1. I may not come next week.
6.1.3. Question: may + subejct + verb + ?
6.1.3.1. May I go to the bathroom?
6.1.4. Have: subject + may + have + participle
6.1.4.1. I may have done something wrong