Expressing degrees of certainty with modal verbs and adverbs

Posted on 19. Aug, 2012 by in English Grammar

Today I would like to talk a little about expressing different degrees of certainty using modal verbs and adverbs.  To keep this discussion as simple as possible I will only be using the modal verb ‘will’, but I will be introducing a number of adverbs that can be used to express degree of certainty with this and other modal verbs.

Let’s start out by discussing what it mean to be certain.  If you are certain about something that means you are sure, but it is important to keep in mind you can be certain in both the positive and negative.  For example you can be certain (or sure) “It will rain.’ or you can be certain or sure ‘It will not (won’t) rain’.

When using the modal verb will to discuss certainty you are talking about the future (not the present or past).  There are different modal verbs you can use to express different degrees of certainty, but you can also use adverbs to express degrees of certainty.  Using different adverbs to express certainty may be easier for you to learn than learning different modal verbs that express certainty.  One of the easiest modal verbs to learn is the modal verb ‘will’ that is used to discuss the future.  Using the modal verb ‘will’ and ‘won’t’ is one of the most common ways of expressing the future, for example:

I will go to school tomorrow.
or
I won’t go to school tomorrow.

There are number of adverbs you can add to simple sentences like these examples that add meaning related to certainty and that don’t require you to become familiar with the use of other modal verbs like: could, would, and  should.

Some of the most common adverbs related to certainty include: certainly, definitely, probably, and possibly.

Here is how these adverbs rank on a continuum in terms of certainty. Keep in mind that if you are ‘unsure’ this means you don’t know, if you are ‘sure’ this means you know something without a doubt.

not sure                     ———->                        sure

possibly —- probably —- certainly —- definitely

Now, you can add these adverbs to sentences about the future (using the modal verb will) to give more meaning about the certainty of future actions.

Here are some examples:

I will probably get home at 5:00pm.
Ezra will certainly be visiting us next week.
Eliza will possibly go out for lunch with her coworkers.
We will definitely be laid off if the company’s income doesn’t improve.

As you can see in these examples the adverbs related to certainty is placed between the modal verb ‘will’ and the action verb of the sentence.  I hope you have found this explanation of how to use adverbs with the modal verb will to express degrees of certainty helpful.  You will definitely get better at expressing degrees of certainty with practice!

Answers to present perfect simple vs. present perfect progressive fill-in-the-blank exercise:
1. I have been eating chocolate everyday since I was a child.
2. How long have you been living in the United States?
3. She has been to the store 10 times today, and now she needs to go again.
4. They have been waiting to see the doctor for over two hours.
5. My computer hasn’t worked well in years.  It is time for me to buy a new one.

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About gabriele

Hi there! I am one of Transparent Language's ESL bloggers. I am a 32-year-old native English speaker who was born and raised in the United States. I am living in Washington, DC now, but I have lived all over the US and also spent many years living and working abroad. I started teaching English as a second language in 2005 after I completing a Master's in Applied Linguists and a Certificate in English Language Teaching to Adults' (CELTA). Since that time I have taught ESL in the United States at the community college and university level. I have also gone on to pursue my doctorate in psychology and now I also teach courses in psychology. I like to stay connected to ESL learners around the world through Transparent Languages ESL Blog. Please ask questions and leave comments on the blog and I will be sure to answer them.

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