Tense
Changes in tense in English are achieved by the changes in ending and the use of auxiliary verbs "to be" and "to have" and the use of the auxiliaries "will", "shall" and "would". (These auxiliaries cannot co-occur with other modals like can, may, and must.) The examples below use the regular verb to listen:

* Present tenses
o Present continuous (or "present progressive"): "I am listening." This tense expresses actions in the present taking place as the speaker is speaking.
o Simple present (or simply "present"): "I listen." This tense expresses actions in the present on a habitual or repetitive basis, but not necessarily happening at the moment the speaker is speaking.
o Present perfect : "I have listened." This tense expresses actions that began in the past but are still true in the present: "I have known her for six years" (and I still know her).
* Past tenses
o Simple past: "I listened." This is used to express a completed action that took place at a specific moment in the past. (Confusingly, in US English, the simple past may sometimes be used for a non-specific moment in the past
o Present perfect or perfect "I have listened." This is used to express a completed action that took place at a non-specific moment in the past. This tense often expresses actions that happen in the past, yet cannot be considered a past tense because it always has a connection to the present.
o Past continuous (otherwise known as the imperfect or past progressive): "I was listening." This is used to express an incomplete action in the past. (Thus an "imperfect" action, as opposed to a completed and therefore "perfect" action.)
o Past perfect or pluperfect: "I had listened." This expresses an action completed prior to some other action in the past (often expressed by the simple past). The pluperfect is thus expressing an action even more in the past e.g "He realised he had lost his way", "I was going to town because he had spoken to me".
o Present perfect continuous: "I have been listening." This is used to express that an event started at some time in the past and continuing to the present.
o Past perfect continuous or simply "perfect continuous": "I had been listening." Usually used with an explicit duration, this indicates that an event was ongoing for a specific time, e.g. "When Peter entered my room, I had been listening to music for half an hour."

* Future tenses
o Simple future: "I shall/will listen." This is used to express that an event will occur in the future, or that the speaker intends to perform some action.
o Future continuous: "I shall/will be listening." This is used to express an ongoing event that has not yet been initiated.
o Future perfect: "I shall/will have listened." This indicates an action which will occur before some other action in the future: Normally two actions are expressed, and the future perfect indicates an action which will occur in the future but will, at the time of the main future action expressed, be in the past (e.g. "I will know the tune next week because I will have listened to it").
o Future perfect continuous or future imperfect: "I shall/will have been listening." Expresses an ongoing action that occurs in the future, before some other event expressed in the future.
o "I am going to listen" is a construction using "to go" as an auxiliary. It is referred to as going to future, futur proche or immediate future, and has the same sense as the simple future, sometimes with an implication of immediacy. It is not strictly a tense, and "to go" is not strictly a tense auxiliary verb, but this construction often presented as a tense for simplicity. By varying the tense of the auxiliary "to go", various other meanings can be achieved, i.e. I am going to be listening (future continuous), I was going to listen (Conditional perfect continuous).

* Conditional tenses
o Present conditional or simply conditional: "I would listen." This is used to express that an event would occur in the future in the past, or that the speaker intended to perform some action.
o Present continuous conditional: "I would be listening." This is used to express an ongoing event that had not yet been initiated.
o Conditional perfect: "I would have listened." Indicates that an action would occur after some other event.
o Conditional perfect continuous: "I would have been listening": Expresses an ongoing action that would occur in the future in the past, after some other event.

Auxiliary verbs may be used to define tense, aspect, or mood of a verb phrase.

As mentioned above "going to" is used for some future pseudo-tenses:

Forms of "do" are used for some negatives, questions and emphasis of the simple present and simple past:

1. "Do I listen?" "I do not listen." "I do listen!"
2. "Did I listen?" "I did not listen." "I did listen!"