Cover of the textbook On Screen B2+ - Student's Book

Exercise 5 — On Screen B2+ - Student's Book

8c - Grammar in use — On Screen B2+ - Student's Book by Virginia Evans and Jenny Dooley from Express Publishing

Question

Read the examples. Which modal verb(s) do we use to say that we are sure something happened / didn’t happen? it's possible / probable that something happened / didn’t happen?