Present perfect and past simple5 Study the examples and answer the questions.a I've learnt a lot this year.b I studied here three years ago.c He's studied at the school since 2008.d He started the school last year.e How long have you lived here?f When did you see Avatar?1 Which sentences are in the present perfecttense and which are in the past simple?2 Which sentences describe an action thatstarted and finished in the past?3 Which sentences describe an action thatstill continues in the present?(More practiceWorkbook page 35)mwenyewe​

Your hands are so dirty! What have you been doing?
I have been repairing my car.
The machine is OK. I have repaired it.
How long have you been reading this book?
Have you read this book?
Where is Dasha and Oleg? - They are playing tennis. They have been playing for 2 hours.
Have you ever played tennis?
This week we have played tennis 3 times.
Today I have written 5 letters.
I have been writing letters all morning today.
It's good to see you again. What have you been doing since we last met?
You've been eating too much recently.
You should eat less.

Environmental problems have become one of the most urgent problems of modern society. More and more people suffer from air and water pollution. Nature also suffers from land and nuclear pollution. The reasons for such environmental problems are numerous. Among them increasing number of cars in the streets, factory waste, millions of cut down trees, destroyed habitats of animals, contaminated rivers and seas. All these problems mainly arise due to human careless activities and gradually destroy our planet. If we look closely, we’ll notice that not only one city is under danger, but the majority of world population. Fortunately, there are many ways to suspend these problems. If everybody starts caring about the planet we live on, many environmental problems can be solved. For example, if we start recycling paper and cardboard, we can save lots of trees. If we start using public transport more than private cars, we can have less air pollution. Local governments can also help to prevent some problems, if they forbid logging companies to destroy the forests, or stop factories from polluting water.