Verbs are mostly action words, and the tense of the verb denotes the time of the action. English has six tenses (present, present perfect, past, past perfect, future, future perfect), and each of these tenses has a progressive (also called "continuous") form. The following discussion outlines the form and use of each of these tenses, first presenting the simple tenses (present, past, and future) and their corresponding progressive tenses, followed by the three perfect tenses and their progressive counterparts. (In each example, the verb that illustrates the defined tense is underlined.)
- Present tense indicates something that is taking place at the time of the speaking or writing or an action that occurs regularly:
> I understand your problem. (Right now, I understand it.)
> She enjoys romantic movies. (She enjoys them regularly.)
- Present progressive tense indicates continuing action that is taking place at the time of the speaking or writing. (Note that the chief difference between simple present and present progressive is that the present progressive action is continuous.)
> The wind is blowing, and it is shaking the leaves from the trees.
> I am suffering from laryngitis; that is why I am speaking softly.
- Past tense indicates an action that has already happened.
> He fell down the stairs yesterday and broke his arm.
> When George failed the test, he became depressed.
- Past progressive tense indicates a continuing action occurring in the past or action occurring at the same time in the past as another action.
> She was arguing with her boss all day yesterday. (Continuing action)
> Bob was talking on his cell phone when he ran into a parked car. ("Was talking" is the continuous action that was occurring when he ran [simple past tense] into a parked car.)
- Future tense indicates an action that will take place – a definite action, an intended action, or a probability.
> Next week the company will conduct training sessions for new employees. (Definite action)
> The college announced that it will require all students to buy computers. (Intention)
> The hurricane will most likely hit the coast by nightfall. (Probability)
- Future progressive tense indicates a continuing action in the future – either generally or at a specific time in the future.
> We will be deducting taxes from your paycheck. (General, continuing future action)
> Next week the company will be conducting orientation sessions for new employees. (Future continuing action in a specific time period.) (Note that there is, in this respect, little difference between simple future tense [will conduct] and future progressive, except that future progressive stresses the continuing nature of the activity.)
- Present perfect tense indicates two types of continuing action – action that began in the past and is now finished or action that began in the past and continues in the present.
> Professor Jones has written a book on the mating habits of zebras. (The continuing action that began in the past – the writing of the book – is completed.)
> He has adored her ever since the day they met. (The continuing action – adoring her – began in the past, with the implication that it continues in the present.)
- Present perfect progressive tense indicates an action continuing from the past into the present and possibly into the future.
> Ever since it became a household fixture, television has been influencing the lives of those who watch it.
> The cost of energy has been increasing each year.
- Past perfect tense indicates an action that occurred before a certain time in the past or an unfulfilled desire in the past.
> By the year 2000, computers had become indispensable in most businesses. (Action occurring before a certain time in the past.)
> John had hoped to graduate from college, but he couldn't pass English. (Unfulfilled desire in the past.)
- Past perfect progressive tense indicates that a past action went on until another action occurred.
> We had been enjoying the picnic until the rain started.
> Before she published her best-selling books, the author had been living in near poverty.
- Future perfect tense indicates an action that will be finished at a certain future time or that one action will be finished before another occurs in the future.
> By Tuesday, we will have collected all the information you need. (Action to be finished at a certain specific time.)
> By the time you get the dinner on the table, I will have died of hunger. (One action will be finished before another occurs.)
- Future perfect progressive tense indicates that an action will continue until a certain future time.
> By the time we get to Phoenix, we will have been driving for three days and three nights.
> By midnight, I will have been doing homework for five solid hours.
Note on the progressive tenses: Observe that the progressive tenses always express continuing action and always involve the appropriate tense of be plus the present participle.
Note on the perfect tenses: Observe that the perfect tenses are formed by using the appropriate form of the auxiliary verb have plus the past participle.
In assembling these notes, I am indebted to The Brief Holt Handbook (Revised 2nd ed.) by Laurie G. Kirszner and Stephen R. Mandell (Harcourt Brace: 1998).