I. Open the brackets. 1. If you (leave) your roller skates on the pass someone (fall) over them.
2. I won’t have enough time tonight. If I (have) enough time, I (write) a letter to my cousin.
3. If she (be) silly as you say, she (not answer) all the questions.
4. Last night Alex ruined his sweater when he washed it. If he (read) the label, he (not wash) it in hot water
5. If I (not study) tonight, I (not pass) my chemistry exam.

Nowadays the most popular problem in the world is the enviromental pollution. The most urgent problems we have with air and water. There are too many factories that produce a huge amount of different things for human needs,but the most important that they pollute rivers and seas with wastes. Also  every second man has a car, so as a result exhaust emissions have increased for even the last 25 years. The second problem in the field of air is deforestation. People cut down too many trees without planting any new instaed of. And as we all know from the biology trees produce oxygen so we can breathe. It is not difficult to predict that in several hundred years  we will probably breathe through the masks. In my opinion there are some ways that can prevent destroying of our world. Human beeings must care about our enviroment. We can can recycle paper, use public transport or biceclesinstead of using private cars. We need to understand that we take the responsibility for our next generations and their lives.

1 Our country has (показатель третьего числа единственного числа глагола в Present Indefinite\simple) the world's (показатель притяжательного падежа имени существительного) largest deposits (признак множественного числа имени сущ) of oil. В нашей стране имеются крупнейшие в мире месторождения нефти.
2 there are many wooden houses (признак множественного числа имени сущ) in tver. В Твери много деревянных домов.
3. he works (показатель третьего числа единственного числа глагола в Present Indefinite\simple) very hard. Он работает очень много.
4 he packs (показатель третьего числа единственного числа глагола в Present Indefinite\simple) goods in bags and boxes. (признак множественного числа имени сущ) Он упаковывает товары в сумки и коробки.