1. Modals for Certainty To think about ‘degrees of certainty’

2. Present Time: “Why isn’t Susie in the class?” She could be sick. She might be sick. She may be sick. 50% sure or less ( possibly, maybe*, perhaps ) She must be sick. 95% sure She is sick. 100% sure Modals (+V.inf) Degrees of Certainty

3. Present Time Negative: “Why doesn’t Susie eat anything?” She may not be hungry. She might not be hungry. 50% sure or less ( possibly, maybe*, perhaps ) She must not be hungry 95% sure ( a best guess ) She couldn’t be hungry. She can’t be hungry. 99% sure ( impossibly ) She isn’t hungry. 100% sure Modals (+V.inf) Degrees of Certainty

4. Past Time: “Why wasn’t Susie in the class?” She could have been sick. She might have been sick. She may have been sick. 50% sure or less ( possibly, maybe*, perhaps ) She must have been sick. 95% sure She was sick. 100% sure Modals (+have + V3) Degrees of Certainty

5. Past Time Negative: “Why didn’t Susie eat anything?” She may not have been hungry. She might not have been hungry. 50% sure or less ( possibly, maybe*, perhaps ) She must not have been hungry 95% sure ( a best guess ) She couldn’t have been hungry. She can’t have been hungry. 99% sure ( impossibly ) She wasn’t hungry. 100% sure Modals (+have + V3) Degrees of Certainty