Read and complete the sentences with the words. life, needs, ecosystem, changed, future, invented, technology, sources
Human environment is a man-made en-invented new technologies. Communication
vironment. It was (1) ... by humans for their became easier and fast across the world.
needs. Before (2)
appeared, humans They formed a man-made (5)
lived in the natural environment. They had
We need a balance between the natural
an environment-friendly life. With time, their and man-made environment. If we use the
(3) ... grew and grew. Humans learnt new natural (6) wisely, we can have a healways to change their environment for their thy balance. We should use our resources
needs.
wisely and learn to save them. Natural reThey learnt to grow crops and animals, and sources like wood, minerals, water and air
build houses. They (4) the wheel, money, are important for (7) ..
If we do not use
trade and business. Transportation became them wisely, we may run out of them one
faster. It became possible after they had day. We should think about our (8).
Lesson 2 What are the alternative sources to fossil fuels?
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1) We always discuss our problems with our parents. 2) We have just sold the last copy of this book. 3) What is the name of the magazine you are reading? 4) Tomorrow at 10 o'clock in the morning we will write an essay. 5) While my mother was pouring tea, I looked through the morning newspapers. 6) When we get home, they will still be preparing dinner. 7) Have you been to the USA? 8) I've never seen this movie before. 9) These people are looking at us. Do you know them? 10) When I got to the station, it was already getting dark. 11) I will inform you of the result. when I'm done. 12) I haven't seen you in ages. What have you been doing lately? 13) I have been trying to explain our plan to you for an hour, and you are not listening to me. 14) His brother has been teaching at the school since 1965. 15) He worked at this plant for about five years when the war broke out. 16) He finished reading the report when I entered the hall.

1. When we ( met) him, he (was going) to the shop. He ( wanted) to buy some food. 2. What were you ( looking) for when I ( opened) the door? 3. Was your daughter ( skating) on the pond from five till six? 4. What were they ( laughing) at when he ( came) in? - They (were laughing) at a funny story. 5. Where was he ( going) when rain (to begin)? - He (was going) to the office. 6. What was she ( playing) when I ( rang) her up? - She (was playing) the violin. 7. Who (was quarrelling) at that time? - His friend (was quarrelling). 8. Beth and Tom (were watching) a TV programme when their mother ( asked) them to help her. 9. Did you ( help) your mother while she (was washing) up? 10. The scientist (were working) in the laboratory when some­body ( switched) off the light. 11. Whom were you (talking) on the phone to, when I came into the room? 12. Jane (was having) a walk in the park when it ( began) to snow. 13. Why were you (not  having) classes at nine o'clock? - Our teacher (was) ill. 14. Yesterday the whole lesson we (were revising) grammar. 15. While Helen (was taking) a shower mother ( washed) the dishes. 16. I (was laying) the table when I ( broke) a plate. 17. When I (met) them in the yard, they (were laughing). 18. She (did not get) up at six o'clock yesterday. She ( got) up at eight. 19. They were just ( leaving) the house when we ( arrived). 20. When he ( came) to the station, his friend was already ( waiting) for him.