Modals in the Past

1. Overview: Modals in the past are used to express degrees of certainty, possibility, or obligation about events that have already occurred. They help convey speculation or judgment about past situations. When using modals in the past, the structure is [modal] + have + past participle. The past participle is necessary to correctly form these expressions. 2. Cases of Usage: Case 1: Must have This modal indicates a strong assumption about a past event that is almost certainly true. Example: She must have left early; the lights are off in her room. Case 2: Might have This modal suggests a possible past action or event without certainty. Example: He might have taken the wrong train, which is why he's late. Case 3: Could have This modal refers to a past ability or a possible action that did not happen. Example: They could have won the game if they had practiced more. Case 4: May have This modal expresses a possibility about a past event, similar to might but slightly more formal. Example: She may have forgotten our meeting time. Case 5: Can't have This modal indicates a strong belief that a past action or event did not happen. Example: He can't have seen the movie; he was out of town. Case 6: Should have This modal reflects a past obligation or advice that was not fulfilled. Example: You should have called me when you arrived.