The copula generally limits the time to present, past, or future time; but it may express all time.

Exercise 15. Development

1. Mary is happy.

2. Mary may be (is perhaps) happy.

3. Mary seems to be (is apparently) happy.

4. Mary must be (is almost surely) happy.

Why did the speaker use the copula is in the first sentence and may be in the second? What was he certain of in the first case and doubtful of in the second?

Is the third copula more nearly like the first or the second? Why? Which copula shows more doubt, may be or seems to be? Can you tell why?

Which is the copula must be more nearly like, the second and third copulas or the first? Which shows more doubt, must be or seems to be?