The word “tense” refers to time. It refers to how verbs show time by their form. The words “sleep,” “sleeps,” and “slept” are really the same word, but they differ with respect to tense. In English, there are really only two tenses by our definition: past tense and present (or non-past) tense. Of course, we can talk about the future too, but English verbs do not have a special form built into them that indicates the future, whereas it does have forms of the verb that show whether it is non-past or past. For example, the verb “walk” has the form “walks” that shows that it is referring to the present (or, at least, non-past) time (e.g., “She walks to the campus every day,” “She flies to Paris next week”). It also has the form “walked” that shows that it is referring to the past (e.g., “I walked home last night.”) Every verb in English has a form ending in “s” (for third person singular, as in “he knows,” “she works”) as well as forms that look identical to the infinitive (as in “I know,” they work”).* These forms indicate non-past time. Past time is reflected in verbs usually by a form ending in the suffix “-ed.” However, many common verbs such as “go,” “see,” “do,” and “get” have irregular forms for indicating past tense. These particular verbs have “went,” “saw,” “did,” and “got” respectively.
One may wonder about “future tense” in English. Some languages have a specific future tense, but, in English, we rely on ways to talk about the future that do not involve additional forms of the verb. To talk about the future, we often use the expression “be going to,” or we use the auxiliary verb “will” to refer to future time. The reason we prefer to refer to “non-past” time in this glossary rather than simply “present,” is that English speakers also use the “present tense” in speaking about the future. For example, when we say “I leave for Tokyo next week,” we are using the “present tense” to speak about the future. It is really the phrase “next week” that indicates the future, not the form of the verb itself.
In the way that we define “tense” in this glossary, the following examples are all in the “past tense”:
I walked to work.
I had walked to work.
I was walking to work.
I had been walking to work.
The following examples are all in the “present tense”:
She walks to work on Mondays.
She is walking to work these days.
She has walked to work for many years now.
She has been walking to work since last year.
Of course, the sentences that are indicated here as being all in the past tense or all in the present tense differ from each other grammatically, but they differ with respect to “aspect” and not to “tense.” (Verbs formed with “has” or “had” show what is called the “perfect” aspect. Those verbs that use a form of “be” combined with the verb in the “-ing” form, show what is called the “progressive” aspect. Verbs that consist of only one word show the “simple” aspect. “Aspect” refers to such notions as completeness, incompleteness, and continuity.)
In common parlance, the term “present tense” tends to be used for what is more specifically termed the “simple present” form, as seen in the above sentence “She walks to work on Mondays.” The term “past tense” tends to be used for what is more specifically termed the “simple past” form, as in “I walked to work this morning.”
Some grammarians use the term “tense” to indicate the form of a verb in connection with both its time and its aspect. Therefore, terms such as “present progressive,” “past perfect,” and “past progressive” are sometimes called “tenses.”
*The verb “be” is unique in English in that it has more forms than other verbs in both the present and past tenses. Whereas all other verbs have only two forms for the present tense (e.g., “go” and “goes,” “see” and “sees”), the verb “be” has three forms (“am,” “is,” and “are”). And, in the past tense, there are two forms rather than just the one form (“was” for the subjects “he,” “she,” and “it” and “were” for the subjects “I,” “we,” “you,” and “they”).