Since is used to give the starting point of actions or situations that continue up to the moment of speaking;it is followed by the reference to the point of time (e.g. since April 24th).
For is used to say how long an action or situation lasts; it is followed by a reference to a period of time (e.g. for three months).
Since: 8 o’clock; he finished school; 2002; last Monday; etc.
For: 2 hours; a week; a long time; ages; etc.
e.g. I have known him since he finished school.
I have known him for a long time.
Exercise 16.Insert since orfor in the following sentences:
1. His father has been a managing director …10 years. 2.We have been friends … school years. 3. She has not written to us … two months. 4. They have not heard from him … he went abroad. 5. I have not met him … a week. 6. She has lived here … 2002.
*The Present Perfect Simpleis used to say that the action is completed and to talk about its result while the Present Perfect Continuous tense emphasizes the continuation of the action, compare:
I have read your book (= I have finished it).
I have been reading your book (= I have not finished it).
The Present Perfect Simple is used to talk about more permanent situation while the Present Perfect Continuous is especially used for more temporary situations, compare:
I have worked for this firm all my life.
I have been working for this firm since last month.
Both tense-forms have nearly the same meaning, the continuous form stressing the process and the simple form emphasizing the result. Thus, both these sentences are correct:
He has lived in Kyiv since 1987.
He has been living in Kyiv since 1987.
But we tend to use the continuous form if it is possible. Sometimes it is not – with the verbs that are not used in Continuous tenses (see p.136). In such cases we use Perfect Simple forms.
Exercise 17. Use the verb in brackets in either Perfect Simple or Perfect Continuous form.
1. He (not to work) very well recently. 2. He (not to work) for years. 3. I (to learn) irregular verbs all afternoon. 4. I (to learn) irregular verbs – ask me any. 5. I am tired – I (to calculate) our expenses all day. 6. I (to calculate) our expenses – we spend too much on clothes. 7. Sorry about the mess - the workers (to install) new computers in my office. 8. The workers (to install) new computers and we can start working now. 9. They (to monitor) the situation since the elections started. 10. They (to monitor) the situation – here is their report.
* Compare the use of Present Perfect and Past Indefinite:
e.g. We havejustseen them (a past action which time is not definite) –Present Perfect.
We saw them last week (a past action, completed at a definite time in the past) –Past Indefinite.
Exercise 18.Use the verbs in brackets in either Present Perfect or Past Indefinite. Pay attention to time expressions.
1. They already (finish) writing their report. 2. They (finish) writing their report two hours ago. 3. Last time we (see) him, he (look) very tired. 4. I (not see) him recently. 5. He (want) to be a star in his childhood. 6. His dream recently (to come) true. 7. Last month they (increase) his salary. 8. They already (increase) his salary to 1200 UAH. 9. At our last meeting we (decide) to sell a part of our assets. 10. Now we can complete our report- they just (provide) us with all necessary information. 11. He (leave) for Kyiv 2 years ago and he (live) there since then. 12. The morning (be) cold and rainy, but since 10 o’clock the weather (change). 13. I (keep) these photos since we first (meet). 14. She (dream) of becoming a well-known economist since she (start) working at our institute. 15. He (have) this computer since this model (appear) in the market.
Exercise 19.Make the following sentences passive.
1. They have already transferred the money. 2. The company has not received the loan yet. 3. We have just sold the last computer. 4. The accountant has already prepared the balance sheet. 5. He has never paid his debts in time. 6. The bank has recently charged the interest on our loan. 7. I have already answered their letter. 8. We have never raised this problem at our meetings. 9. He has already applied for a loan. 10. She has just calculated our revenues for the last quarter.