What you'll learn
By the end of this lesson, you'll be able to express probability: how likely something is to happen or be true.
When do I use it?
Probability sits between possibility and certainty:
- Good chance: "should", "ought to": "The train should arrive soon." (expected)
- Probable: "probably", "likely": "It will probably rain." "He's likely to accept."
- Almost certain: "bound to": "They're bound to win."
Use "should" for expectations based on normal circumstances: "The repair should take an hour." It is not about obligation here.
How do I form it?
should / ought to + base verb (expected result) be likely / bound + to + verb probably + verb
- The parcel should arrive on Thursday.
- She ought to pass the exam easily.
- Prices are likely to keep rising.
- He's bound to be angry about this.
Common mistakes for Spanish speakers
"Debería" expresses both obligation and probability in Spanish, but in English "should" for probability means "I expect it to happen": "should arrive soon" ≠ "must arrive soon". Do not use "probably" with "should" redundantly ("probably should arrive" is odd), and note "ought to" keeps the "to" while "should" does not. For the past, "should have + participle" expresses expectation or regret, not certainty.
should/ought to = expected. likely to/bound to = probable. Distinguish from must (certainty) and obligation.
Practice
Multiple Choice
C1Which sentence expresses an expectation?
Fill in the Blank
C1He's bound win the competition.
Hint: be bound + to + verb.
Find the Error
C1Sentence Transformation
C1Task: Rewrite with 'is likely to'
Hint: be likely + to + verb.
Practice Speaking
Apply what you've learned in a real conversation with AI feedback.
Level: C1