Active and Passive Modals

1. Active Continuous

1.1. Subject + modal verb + verb infinitive "be" verb +ing (+object)

1.1.1. They must be checking the car now.

2. Passive Perfect Continuous

2.1. Subject + modal verb + have + verb past participle "been" ("be") + verb +ing + past participle verb.

2.1.1. The car must have been being checked as I saw it in the workshop.

3. Active Perfect Continuous

3.1. Subject + modal verb + have + verb past participle "been" ("be") + verb +ing (+ object)

3.1.1. The mechanic must have been checking the car as I saw it in the workshop

4. Passive Simple

4.1. Subject + modal verb + verb infinitive "be" + past participle verb (+ adverb)

4.1.1. Cars should be checked regularly.

5. Passive Perfect Simple

5.1. Subject + modal verb + verb infinitive "have" + past participle verb "be"

5.1.1. The car must have been checked by now.

6. Passive Continuous

6.1. Subject + modal verb + be (verb infinitive) + verb +ing + past participle verb (+ adverb)

6.1.1. The car must be being checked now.

7. Active Simple

7.1. Subject + modal + infinitive verb (+ object)

7.1.1. People should check their cars regularly

8. Active Perfect Simple

8.1. Subject + modal verb + have + verb past participle (+ object)

8.1.1. They must have checked the car by now.