Modals for speculation

• Present

• Must + verb (100% )
• Might + verb (49%)
• May + verb (51%)
• Could + verb (50%)
• Can't be (impossible)
• Has to + verb (75%)

• Modals analysis

We use...

• must, if it is necessary or we are sure something is true.
• ought to / should, if it is a good idea or it is the right thing to do.
• Can / may / might / could, if it is possible to be true.
• Can't, if we are sure it is not true.