I can tell you whether the machine is good when I have tried it.

II. The Present Perfect Durative (Inclusive)

1. It expresses an action which began before the moment of speaking and continues into it. This grammatical meaning is mainly expressed by the Present Perfect Progressive. However the Present Perfect Durative is found with verbs that cannot be used in the progressive form. The whole period of the duration of the action may be marked by prepositional phrases with for.

The starting point of the action is indicated by the adverb since.

• I've been here ever since I came to Paris.

We've known this man for years.

He has had a beard for as long as I can remember.

The Present Perfect Durative is preferred to Present Perfect Progressive in negative sentences when it is the action itself that is completely negated (the Inclusive Present Perfect Tense).

• I haven't driven for a long time.

I haven't worn evening dresses for ages!

2. It may also express an action that began in the past, continued for some time and has just stopped (the Present Perfect Resultative).

• I have been so anxious to meet you.

We haven't seen each other for years!

3. Care should be taken to distinguish between the use of the Present Perfect and the Past Indefinite when the period of duration is expressed by a prepositional phrase with for. If the period of duration belongs to the past, the Past Indefinite should be used. If the period of duration comes close to the moment of speaking or includes it, the Present Perfect is used.

• 'I have lived like this for two years,' he said, 'and I can't stand it any more.

• I teach history at a secondary school. I went to University here for four years and got a degree.

• Yesterday he waited for her for two hours but she didn't turn up.

The present perfect progressive

I. The Present Perfect Progressive is an analytical form which is built up by means of the auxiliary verb to be in the Present Perfect and the ing-form of the notional verb (Participle I).

• I have been working.

She has been reading.

In the interrogative form the first auxiliary verb is placed before the subject.

• Have you been working?

Has she been reading?

In the negative form the negative particle not is placed after the first auxiliary verb.

• We have not been reading.

They have not been working.

In spoken English the contracted forms are used: I've, he's, she's, it's, we've, you've,

they've, hasn't, and haven't.

II. This tense is found in present time contexts, i. e. conversations, newspapers and radio reports, lectures and letters. It has two uses — the Present Perfect Progressive Durative (Inclusive) and the Present Perfect Progressive Resultative (Exclusive).

1. The Present Perfect Progressive (Inclusive) serves to express an action in progress which began before the moment of speaking and continues into it. In this case either the starting point of the action or the period of time during which it has been in progress is usually indicated.

• It has been raining ever since midnight, and it's still drizzling. I've been writing since morning and so I shall soon stop.

All these forms are translated into Russian by the Present Tense, imperfective (дождь идет, я пишу).

2. The Present Perfect Progressive (Exclusive) serves to express an action which was in progress quite recently and which in one way or another affects the present situation, explains the state of things at the present moment. In this case, as a rule, there is no indication of time.

• Don't tell your mother what I've been saying.