Modal verbs of deduction are modal verbs that are used to express a degree of certainty or possibility about a future event or situation. There are different modals of prediction that convey different levels of certainty, such as will, be going to, should, may, might, could, and can’t. Here is a brief explanation of each modal of prediction and some examples of how to use them:
- Will is used to express a strong or confident prediction based on evidence, logic, or intuition. For example:
- It will rain tomorrow. (based on weather forecast)
- She will pass the exam. (based on her preparation)
- He will be happy to see you. (based on his personality)
- Be going to is used to express a prediction based on present evidence or intention. For example:
- Look at those dark clouds. It is going to rain soon. (based on present evidence)
- I am going to visit my grandparents next week. (based on present intention)
- They are going to get married. (based on present plan)
- Should is used to express a prediction based on expectation, assumption, or normality. For example:
- The train should arrive in 10 minutes. (based on schedule)
- He should be home by now. (based on assumption)
- It shouldn’t be too cold in April. (based on normality)
- May, might, and could are used to express a prediction based on possibility or uncertainty. They are often interchangeable, but may is slightly more formal and could is slightly more tentative. For example:
- She may/might/could come to the party. (based on possibility)
- He may/might/could be working late. (based on uncertainty)
- It may/might/could snow tomorrow. (based on low probability)
- Can’t is used to express a negative prediction based on impossibility or contradiction. For example:
- He can’t be 40 years old. He looks much younger. (based on contradiction)
- She can’t have left already. Her car is still here. (based on impossibility)
- It can’t be true. He would never lie to me. (based on disbelief)
To talk about predictions in the past, we can use the same modals of prediction with have and the past participle of the main verb. For example:
- He must have been tired. He fell asleep on the sofa.
- She was going to call me, but she forgot.
- They should have arrived by now.
- He may/might/could have missed the bus.
- She can’t have seen me. I was hiding behind the door.
