Electronic commerce, commonly known as e-commerce or eCommerce, consists of the buying and selling of products or services over electronic systems such as the Internet and other computer networks. The amount of trade conducted electronically has grown extraordinarily since the spread of the Internet. A wide variety of commerce is conducted in this way, spurring and drawing on innovations in electronic found system, suply chain management, internet marketing, online transactons, systems, and automated data collection systems. Modern electronic commerce typically uses the world wide web at least at some point in the transaction's lifecycle, although it can encompass a wider range of technologies such as e-mail as well.





Exercise 1:
1. Where is Tim? I haven't seen him all day
2. Do you like Bratislava? I don't know. I haven't been in Bratislava in my life.
3. Do you like Franco Zeffirelli's films? Yes, I have seen "Rome and Juliet" about 50 times.
4. I hurt my leg skiing. I haven't worked in about a month.
5. Can I ask you a question? Have you seen my sister today?
6. Oh fantastic!! Now I have missed the train!!!
7. My brother works for the government. He has spoken with the President many times
8. I haven't entered a pub since my son was born.
9. I want that report Dalton!!! I'm sorry I haven't finished it yet.
10. Diana doesn't know about the party because I haven't told her.
11. Would you like some dinner? No thanks. I have eaten already
12. Have you seen my slippers? Yes, they are under the bed.





Exercise 2:
1. Where is Tom? - I haven 't seen him today, but he told Mary that he'd be in for dinner.
2. I bought this in Bond Street. - How much you did you pay for it? - I paid .f.l00.
3. Where did you find this knife? - I found it in the garden. -Why didn't you leave it there?
4. I have lost my black gloves. Have you seen them anywhere? - No, I haven 't. I´m afraid I When did you last wear them? - I wore them at the theatre last night. - Perhaps you left them at the theatre.
5. Do you know that lady who have just left the shop? -Yes, that is Miss Thrift. Is she a customer of yours? -Not exactly .She has been in here several times but she has never bought anything.
6. He left the house at 8.00. - Where did he go? - I didn't see where he went.
7. He served in the First World War. – When did the war begin? -It began in 1914 and lasted for four years.
8. Who did you vote for at the last election? - I voted for Mr. Pitt. - He wasn't, was elected, was he? - No, he lost his deposit.
9. Did you like your last job?- I liked it at first but then I Quarrelled with my employer and he dismissed me. - How long you were there? - I was there for two weeks.
10. I didn't know that you knew Mrs. Pitt. How long have you known her? - I have know her for ten years.
11. That is Mr. Minus, who teaches me mathematics, but he hasn't had time to teach me much. I only have been in his class for a week.
12. Did you hear his speech on the radio last night? - Yes, I did. What did you think of it? '
13. I didn't know that you were here. Have you been here long? - Yes, I have been here two months. - Have you been to the Cathedral? - Yes, I went there last Sunday .
14. Have you ever tired to give up smoking? -Yes, I tired last year , but then I found that I was getting fat so I started again.
15. Have you seen today's paper? - No, has anything interesting happened? Yes, two convicted murderers have escaped from the prison down the road.
16. Has Mary fed the cat? - Yes, she fed him before lunch. - What did she give him? - She gave him some fish.
17. How long have you known your new assistant? - I have known him for two years. –What did he do before he came here? - I think he was in prison.
18. I haven 't seen your aunt recently .No. She hasn't been out of her house since she bought her colour TV.
19. Was the plumber been here yet? - Yes, but he only stayed for an hour.- What did he do in that time? - He turned off the water and emptied the tank