Grammar practice Section. 1. Present perfect – present result of a past event a

Perfect tenses. 1. Match the sentences with the explanations.

1. present perfect – present result of a past event	a. Before he left the company he had been putting together a software package.
2. present perfect – present situation that started in the past	b. People have been using computers for different purposes - both good and bad.
3. present perfect - unfinished period of time	c. I was sure I had deleted all the client records.
4. present perfect continuous - action in progress from the past up to the present	d. The update process had been running for 20 minutes when the computer suddenly crashed.
5. present perfect continuous - emphasis on the duration of time	e. I have already checked all our records today and it’s only lunchtime.
6. present perfect continuous – actions repeated over a period of time	f. He had installed the new software and then restarted the computer.
7. past perfect – emphasis on the action that happened before another past event/moment	g. The antivirus has been running for over an hour and there is still more than 60% left.
8. past perfect + verb of thinking	h. The latest data input has overwritten the old information.
9. past perfect continuous – situation that was in progress up to a certain point in the past	i. He goes there once a week to check computer systems. He has been going there for several months already.
10. past perfect continuous - emphasis on the duration of time	j. The new operation system has been installed on our computers since we hired this engineer.

2. Put the verbs in brackets into the correct perfect tense form.

1. A solid working knowledge of productivity software and other IT tools (become) a basic foundation for success in virtually any career nowadays.
2. Before the new program superseded the earlier one our work (be) much slower.
3. With this system we (eliminate) all possibilities of error.
4. The latest version of our award-winning image-editing software (increase) in popularity for the last several weeks.
5. The brand new, friendly drag-and-drop interface (allow) me to get more productive.
6. The capabilities of the PC (change) greatly since the introduction of electronic computers.
7. The file (download) for more than an hour and it still shows only 18 percent!
8. They (re-design) the software adding wizards and tutorials that explain complex procedures and their sales increased dramatically.
9. Older people (suffer) from computer anxiety in recent years.
10. The tech support officer thought the client (press) the wrong key.
11. As I (save) this file in the wrong directory I couldn’t find it when I needed it.
12. The maintenance engineers (try) to identify the cause of the system failure for several hours before they managed to.
13. The use of computers in all spheres of life (increase) over the last few decades.
14. Before the invention of home computers and the Internet people (spend) more time outdoors.
15. By the end of the 20th century metal wires (be) replaced by fiber-optic ones.
16. Human beings always (seek) for a machine to help them make their lives easier and at last computer was created.

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