purpose a. method
data b. surveyor
along with c. aim
imply d. establish
observer e. information
technique f. mistake
compute g. together
accurate h. measure
error i. precise
determine j. mean

1. Environmental pollution causes ... to people's health. D damage
2. Everyone should learn about using ... resources responsibly. B natural
3. The wildlife park was created to protect ... species. B endangered
4. We should try to reduce our water ... . A consumption
5. The cost of cleaning up toxic ... is very high. A waste
6. If we cut down these trees, we will destroy the natural ... of the birds and animals that live in them. D habitat
7. What is the future of genetically ... food?  B modified
8. One of the major environmental ... that needs to be considered is deforestation.
C issues
9. Global is causing climate changes.  D warming
10. We must investigate … energy forms.  B alternative

1At last I have done my homework.
I did my homework after school yesterday.
2I have been to England.
I wad in England last summer.
3I have just written a letter to my granny.
I wrote s letter to my granny yesterday.
4What book have you recently read?
What book did you read last week?
5I haven't seen my friend since Monday.
I saw my friend last Monday.
6While travelling to England I met many friends.
I met many friends last summer holidays.
7I have never spoken to him.
I spoke to him five minutes ago.
8Why have you left the door open.
I left my flat at eight o'clock yesterday.
9Look!I have bought a new dress!
I bought a new dress two hours ago.
10The rain has stopped and I can go for a walk.
The rain stopped an hour ago.