In a previous article I discussed the problems the learner of English faces in deciding which tense to use when talking about a past event. I concentrated in that article on the choice between the past simple and the present perfect. In fact, however, the present perfect has two forms, the simple form and the continuous form, and so the choice is even more complicated than it might seem at first!
The following sentences are examples of the two present perfect forms:
The problem for the learner in deciding which of the forms to use is that in some cases they have identical (or almost identical) meanings, in other cases they each have a different meaning; and in yet other cases only one of the forms is possible.
1.) As an example of a case when the two forms (simple and continuous) have more or less the same meaning, look at the following sentences:
There is a very slight hint in the second of each of these sentences that the action or state may be temporary, but only the most advanced learner of English need be concerned with this distinction.
2.) The next pairs of sentences are examples of when the two forms have different meanings.
In the first sentence (of the first example) the speaker wants to emphasise that he has finished learning all the verbs and now knows them. In the second sentence the speaker wants to point out that he has spent some time learning the new words, but it is not clear whether he has finished learning them all or not. A similar explanation applies to the second example.
3.) Finally, there are many occasions when only one of the two forms is possible. Look at the following pairs of sentences:
In the first example, the verb had (in the sense of possess) cannot be used in the continuous form and so the second sentence is impossible. In the second example, the first sentence is incorrect because it does not convey the duration of the action.
So, are there any useful rules that can help the learner select the correct verb from this jumble of possibilities? In fact there are, and they are summarized below:
With these rules in mind, look at the following pairs of sentences and decide if both are possible or not. If they are both possible, try to explain the difference in the intention or meaning of the speaker that used them. Let's start with two of the examples from the introduction:
(You are standing on the street corner waiting for a friend. When she arrives, she apologises for being late. How do you reply?)
(Imagine the situation at a party where your wife has just returned to the room after a short absence. What do you ask?)
Both of these sentences are possible and they have the same meaning. There is a slight hint in the second sentence that the speaker regards his stay in Frankfurt as temporary.
These are both possible, but have different meanings. The first sentence could be said by a mother who hears a crashing noise in her son's room and goes in to ask him what has happened. In the second sentence the son has returned from his room and his mother wants to know how he has been occupying himself over the last few hours.
The second sentence is much more likely than the first. The speaker is emphasising the duration of the action (waiting) and so uses the present perfect continuous.
In the first sentence the speaker seems to be asking "Who are all the people you talked to in the other room. This is possible but not as likely as the second sentence. In this one, you are implying that your wife had only one conversation partner and you are interested to know who it was that she was talking to for so long.
Only the second sentence is likely. The questioner is interested in the activity of crying, not in the fact that it is finished, as implied by the use of the present perfect simple in the first sentence.
The first answer sounds much better. The very question "how long?" indicates that the speaker is concerned with the duration of the activity.
The first sentence is much more likely than the second one. The speaker is asking how many books the brother has completed. The second sentence is just possible in a situation where the author is always writing many books at the same time, and the questioner wants to know how many books he has been writing over the recent time period.