All verbal forms – both finite and non-finite – are characterized by as­pectual meanings (cf. to have written, having written), but finite forms are impossible without temporal parameters and meanings. In correlation be­tween tense and aspect in finite forms, aspect is a permanent characteristic of a class, whereas tense is obligatory but variable (Present Progressive -Past Progressive – Future Progressive).

Since the present tense is essentially used to describe, rather than to narrate, it is essentially imperfective, either progressive or habitual, and not perfective.

In English, a sentence like he comes here on its own, in present, will normally be interpreted with habitual meaning, since if the reference were to an action going on at the present moment, it would have to be he is com­ing here, i.e. in the Progressive. However, in a context where he comes here does not have present time reference, then perfective meaning is a possible interpretation, as in a subordinate clause of time, e.g. when he comes here, I’ll tell him, since the verb comes refers to a future action.

One interesting facet of the general problem of the relation between tense and aspect can be studied by examining cases where languages use one tense in place of another, for instance in the narrative present, where the present tense is used to refer to a past situation. A simple English ex­ample would be the use of I’m sitting on the veranda when up comes Joe and says…rather than / was sitting on the veranda when up came Joe and said…In English the non-Progressive Present of nonstative verbs tends to be restricted to expression of habitual actions. Another use of this non-Progres­sive Present is in the historic Present, where the aspect distinction Progressive/non-Progressive of the Past is retained. A similar use of the non-Pro­gressive Present is what may be called the commentary use of the Present, as in providing a commentary for a film, a football match, or a horse-race (simultaneous narration).

Here, although we are in present time, the struc­ture of the communication is that of a narrative. This characteristic structure is reflected in the possibility of using the non-Progressive Present to refer to complete actions, i.e. to maintain an aspect distinction just as one would in the past tense, the only difference being that here the maintenance of the distinction is optional, since as in the present tense generally the Progressive can be used for all non-habitual actions, thus a film commentary might be as follows:

Now the villain seizes the heroine, now they drive off towards the rail­way track, now he forces her out of the car, now he ties her to the track, while all the time the train is getting nearer.

(All verb forms except the last are non-Progressive.) Equally, the com­mentary could have been given throughout in the Progressive form:

Now the villain is seizing the heroine, now they’re driving off towards the railway track, now he s forcing her out of the car, now he s tying her to the track, while all the time the train is getting nearer.

One factor influencing the choice between the two possibilities is that the non-Progressive is favoured when a rapid series of events has to be com­mented on as they are happening.