MẪU CÂU TIẾNG ANH VỀ TALKING ABOUT CERTAINTLY & PROBABILITY

Karen and Linda made plans to go shopping one night at 7:00 PM. Karen is at Linda’s house, but Linda isn’t there – so Karen calls Linda’s brother, Eric, to ask for information. Listen to their conversation to learn phrases for expressing certainty and probability.

Conversation Vocabulary and Phrases

In this dialogue, Karen and Eric discuss various possibilities about where Linda is at the moment. Some things they are certain about, and other things they are not completely certain about – so they need to guess.

If you are 100% certain that something is true, you can say:

•  “I’m (quite) certain that...”
•  “I’m (absolutely) positive that...”
•  “I have no doubt that...”
•  “It’s definitely...”

Sometimes, to support a statement, you want to use external evidence like popular agreement or scientific facts. For example:

•  “It’s common knowledge that...”
•  “Everybody knows that...” / “It’s no secret that...”
•  “Few people would deny that...”
•  “It’s a well-established fact that...”
•  “It has been proven that...”

If you make a logical deduction that you are certain is true/correct, you can use must (for situations in the present) or must have (for situations in the past):

 “There’s no signal on my cell phone. We must be out of range of a cell phone tower.”
 “Her car isn’t here – she must have gone out.”

Now, if you are mostly certain about something, but not 100%, you can say, “I’m pretty sure...” as Eric says in the dialogue: “I’m pretty sure she’s at home.”

When you’re not sure about something, you can guess or imagine the possibilities or probabilities.

These phrases are used for guessing with a strong degree of certainty:

•  “There's a good chance...”
•  “The odds are...”
•  “Probably.”
•  “It's (very) likely.”
•  “I bet...”

And these phrases are used for guessing with less certainty:

•  “I guess...”
•  “It seems that...”
•  “It’s possible.”
•  “I wouldn't be surprised if...”

We can also use might and could for possibilities in the present (or future), and might have and could have for possibilities in the past:

•  “It might rain tomorrow.”
•  “The floor is wet – there might be a leak in the refrigerator... or someone might have spilled some water.”
•  “If your computer isn’t working properly, it could be infected with a virus.”
•  “I could have gotten a better job if I had studied harder in school.”

To say that something is not probable, use these phrases:

•  “It's unlikely / not likely.”
•  “There's not much hope / chance.”
•  “I'd be very surprised if... (+ past participle)”

                 Ex) “I’d be very surprised if that team won the championship next week.” We use the past participle even though the event is in the future!

•  “I don't expect... (+ to + verb)”

                Ex) “I don’t expect that team to win the championship next week.”

Finally, to say something is not possible at all, use these phrases:

• “It's impossible.”
• “There's no chance that...” 
• “That would never happen.” / “That couldn’t have happened.”

The second phrase is only for things in the past

•  “That can’t be true.”

You can use can’t (present/future) and couldn’t have (past) to express impossibilities:

•  “You can’t buy beer – you’re only 15!”
•  “Steve couldn’t have bought the beer – he’s only 15. An older friend must have bought it for him.”

As you can see, “can’t have” is used for the impossible part (15-year-old Steve buying the beer) and “must have” is used for the probable or certain part (an older friend buying the beer for Steve).

For additional clarification on the topics of may and might as well as could have, should have, and would have, check out these lessons:

•  May and might
•  Should have, could have, would have
•  Modal verbs for deduction

You’ve finished Lesson ! Now take the quiz to practice the phrases for certainty and probability.

Quiz – Lesson 35

1) Who took my magazine? I'm absolutely __________ that I left it on this table, and now it's not here.

A. established

B. optimistic

C. positive

2) Where's Mike? He ___________ gone out because his keys are still here.

A. couldn't have

B. might not have

C. must have

3) Tim has missed two classes this week. He ________ be sick... or maybe he's just traveling.

A. can't

B. could

C. would

4) There's a good _________ that I'll get a promotion soon!

A. chance

B. guess

C. opportunity

5) That car is so expensive! They __________ spent at least $100,000 on it.

A. can't have

B. must have

C. shouldn't have

6) It's very __________ that Bill Jones will retire this year - he turns 65 in February.

A. likely
B. probably

C. surprising

7) It has been ___________ that too much sitting causes significant health risks.

A. definitely

B. knowledgeable

C. proven

8) I'm _______ sure I turned off the lights upstairs... but could you please go check, just in case I didn't?

A. clearly

B. pretty

C. really

9) I'm not sure what's causing my headache. It could be stress... or I _______ not be getting enough sleep.

A. doubt

B. expect

C. might

10) I wouldn't be ________ if my daughter Sarah became a veterinarian when she grows up - she loves animals.

A. certain

B. possible

C. surprised

11) Everyone was late for work this morning. I haven't seen the boss yet, but I _________ he's angry.

A. bet

B. must

C. seem

12) Dan was very seriously injured in the accident. Sadly, the doctors say there's not much _______ he'll survive.

A. case

B. hope

C. likely

13) Carla has worked as a gourmet chef for 20 years - she ________ be an amazing cook!

A. can't

B. might

C. must
14) After doing lots of research, I have no _________ that this is the product we need.

A. doubt

B. fear

C. insecurity

15) A breakdown of the machinery? That couldn't have __________, it was in perfect condition. The person operating it must have done something wrong.

A. been certain

B. expected

C. happened

Lesson 35 Quiz – Answers

1.C 2.A 3.B 4.A 5.B 6.A 7.C

8.B 9.C 10.C 11.A 12.B 13.C 14.A 15.C