Adverbs of possibility Adverbs of possibility are used to show how certain we are about a situation or event. Words such as definitely, certainly and obviously are used to show that we are almost sure that something will happen. Adverbs such as probably, possibly and maybe are used when we are less certain that something will happen. These are all known as adverbs of possibility. We are obviously delighted to say that our latest set of pages covers adverbs of possibility and can now be found as part of our extensive range of worksheets on adverbs. They will certainly ensure that children understand exactly what adverbs of possibility are and how to use them. Go to English: Grammar: Adverbs