Adverbs that change or qualify the meaning of a sentence by telling us when things happen are defined as adverbs of time.
An adverb of time is just what you might expect it to be - a word that describes when, for how long, or how often a certain action happened. You will notice that many adverbs of time are the same as adverbs of frequency. There is quite a bit of overlap between these two types of adverbs - so much so that some instructors choose to mention one or the other but not both.
These simple rules for adverbs of time will help you to use them the right way:
Each sentence contains an example of an adverb of time; the examples are italicized for easy identification.
Are you coming to work tomorrow?
I'd like to go to the movies later.
Jim was so sick he spent four weeks in the hospital.