Let’s start with a mystery. Your friend isn’t answering her phone. Where is she? You can say: ‘She may be at work.’ Or ‘She might be sleeping.’ Or ‘She could be in a meeting.’ All three are correct! May be, might be, and could be all express the same thing – you’re guessing because you’re not sure.

Here’s the first key point: these are modal verbs that come BEFORE the main verb ‘be’. The structure is: subject + modal + be + place or activity. ‘He may be tired.’ ‘They might be busy.’ ‘It could be broken.’

Now, be careful! Many learners confuse ‘may be’ (two words, a modal verb) with ‘maybe’ (one word). Here’s the crucial difference: ‘Maybe’ is an adverb that starts a sentence. ‘May be’ is a verb that comes after the subject. Compare these: ‘Maybe she’s at home’ versus ‘She may be at home.’ Both mean the same thing, but the grammar is completely different. The same pattern works with ‘perhaps’ and ‘possibly’ – these are also adverbs like ‘maybe’. You say: ‘Perhaps he’s late’ or ‘He may be late.’ Not ‘He perhaps is late.’

The second important point: you can also use continuous forms for actions happening right now. ‘She might be working.’ ‘He could be driving.’ ‘They may be eating dinner.’ The structure becomes: subject + modal + be + verb-ing. This shows you’re guessing about an action in progress.

Now let’s travel to the past. Imagine your friend didn’t come to the party yesterday. You can guess why: ‘She may have been sick.’ ‘She might have been tired.’ Notice the structure changes: subject + modal + have been + adjective. This is how we speculate about past situations.

The third key teaching point: for past actions, use the continuous form. ‘He may have been working.’ ‘They might have been sleeping.’ The structure is: subject + modal + have been + verb-ing. This guesses about past actions in progress.

Here’s a common mistake: learners often say ‘She may was tired’ or ‘He might had a meeting.’ Wrong! Always use ‘may/might/could + be’ for present and ‘may/might + have been’ for past. Never use ‘was’ or ‘had’ after these modals.

One quick note about ‘must be’ and ‘must have been’: these are different. When you say ‘She must be at home,’ you’re not guessing – you’re making a deduction. You’re almost certain. But ‘She may be at home’ is true speculation – you’re really not sure. The difference is about how confident you feel.

Let me give you the fourth key contrast: all three modals (may, might, could) express the same level of uncertainty for speculation. Some grammar books say ‘might’ is less certain than ‘may,’ but in modern English, native speakers use them interchangeably when guessing. ‘It may be true,’ ‘It might be true,’ and ‘It could be true’ all mean exactly the same thing.

Here’s your practice moment: Look around you right now. What can you see? Make three guesses using different modals. ‘That person might be going to work.’ ‘The weather could be changing.’ ‘Someone may be cooking dinner nearby.’ Try using the past forms too: ‘That car might have been expensive.’ ‘The shop may have been closed yesterday.’

Remember the golden rule: when you’re not sure, use may be, might be, or could be. When you want to start your sentence differently, use maybe, perhaps, or possibly. And for the past, add ‘have been’ after your modal. These small words make you sound much more natural and less direct – very important in English!