The English tense–aspect system has two morphologically distinct tenses, past and non-past, the latter of which is also known as the present-future or, more commonly and less formally, simply the present. No marker of a distinct future tense exists on the verb in English; the futurity of an event may be expressed through the use of the auxiliary verbs will and shall, by a non-past form plus an adverb, as in tomorrow we go to New York City, or by some other means. Past is distinguished from non-past, in contrast, with internal modifications of the verb. These two tenses may be modified further for progressive aspect (also called continuous aspect), for the perfect, or for both. These two aspectual forms are also referred to as BE +ING[13] and HAVE +EN,[14] respectively, which avoids what may be unfamiliar terminology.

Aspects of the present tense:

• Present simple (not progressive, not perfect): I eat
• Present progressive (progressive, not perfect): I am eating
• Present perfect (not progressive, perfect): I have eaten
• Present perfect progressive (progressive, perfect): I have been eating

(While many elementary discussions of English grammar classify the present perfect as a past tense, it relates the action to the present time. One cannot say of someone now deceased that they have eaten or have been eating. The present auxiliary implies that they are in some way present (alive), even when the action denoted is completed (perfect) or partially completed (progressive perfect).)

Aspects of the past tense:

• Past simple (not progressive, not perfect): I ate
• Past progressive (progressive, not perfect): I was eating
• Past perfect (not progressive, perfect): I had eaten
• Past perfect progressive (progressive, perfect): I had been eating

Aspects can also be marked on non-finite forms of the verb: (to) be eating (infinitive with progressive aspect), (to) have eaten (infinitive with perfect aspect), having eaten (present participle or gerund with perfect aspect), etc. The perfect infinitive can further be governed by modal verbs to express various meanings, mostly combining modality with past reference: I should have eaten etc. In particular, the modals will and shall and their subjunctive forms would and should are used to combine future or hypothetical reference with aspectual meaning:

• Simple future, simple conditional: I will eat, I would eat
• Future progressive, conditional progressive: I will be eating, I would be eating
• Future perfect, conditional perfect: I will have eaten, I would have eaten
• Future perfect progressive, conditional perfect progressive: I will have been eating, I would have been eating

The uses of the progressive and perfect aspects are quite complex. They may refer to the viewpoint of the speaker:

• I was walking down the road when I met Michael Jackson's lawyer. (Speaker viewpoint in middle of action)
• I have traveled widely, but I have never been to Moscow. (Speaker viewpoint at end of action)

But they can have other illocutionary forces or additional modal components:

• You are being stupid now. (You are doing it deliberately)
• You are not having chocolate with your sausages! (I forbid it)
• I am having lunch with Mike tomorrow. (It is decided)

English expresses some other aspectual distinctions with other constructions. Used to + VERB is a past habitual, as in I used to go to school, and going to / gonna + VERB is a prospective, a future situation highlighting current intention or expectation, as in I'm going to go to school next year.