Progressive

The progressive or continuous aspect is used to denote a temporary action or state that began at a previous time and continues into the present time (or other time of reference). It is expressed using a form of the auxiliary verb to be (conjugated appropriately for tense etc.) together with the present participle (-ing form) of the main verb: I am reading; Were you shouting?; He will be sitting over there.

Certain stative verbs make limited use of progressive aspect. Their nonprogressive forms (simple or nonprogressive perfect constructions) are used in many situations even when expressing a temporary state.

The main types are described below.

• The copular verb to be does not normally use progressive forms (I am happy, not I am being happy). However its progressive aspect is used in appropriate situations when the verb expresses the passive voice (We are being followed), and when it has the meaning of "behave" or "act as" (You are being very naughty; He's being a pest).
• The verb to have does not use progressive forms when it expresses possession), broadly understood (I have a brother, not I'm having a brother), but it does use them in its active meanings (I'm having a party; She's having a baby; He was having a problem starting his car). Other verbs expressing a state of possession or similar, such as possess, own, belong and owe, also do not normally use progressive forms.
• Verbs of mental state, sense perception and similar (know, believe, want, think, see, hear, need, etc.) are generally used without progressive aspect, although some of them can be used in the progressive to imply an ongoing, often temporary situation (I am feeling lonely), or an activity (I am thinking about a problem).
• Verbs denoting positional state normally do use the progressive if the state is temporary: He is standing in the corner. (Compare permanent state: London stands on the banks of the Thames.)

Perfect Progressive

The perfect and progressive (continuous) aspects can be combined, usually in referring to the completed portion of a continuing action or temporary state: I have been working for eight hours. Here a form of the verb have (denoting the perfect) is used together with been (the past participle of be, denoting the progressive) and the present participle of the main verb.

In the case of the stative verbs, which do not use progressive aspect, the plain perfect form is normally used in place of the perfect progressive: I've been here for half an hour (not I've been being here...).