Fill in the blanks with the correct modal
Well, if your wallet is empty, you ______ all your money.

must have spent

The correct modal to fill in the blank is must have spent. The modal must have is used to express certainty about something that happened in the past, and it is the most appropriate modal to use in this context because it conveys the idea that the person must have spent all their money because their wallet is empty.

The other options are incorrect. The modal should have spent suggests that the person should have spent their money, but this is not certain. The modal ought to have spent is similar to should have spent, but it is more formal. The modal could spend expresses possibility, but it does not convey the same sense of certainty as must have spent.