12. I (not come) to London till the bus strike (be) over.
13. He (ring) us up when he (arrive) in England?
14. He (wash up) before he (go) to bed.
15. I (arrive) at 10 am unless there (be) traffic.
16. He (be) here before you (go).
17. I (pay) you when I (get) my cheque.
18. I (go on) doing it until he (tell) me to stop.
19. When I (have) enough money, I (buy) that house.
20. When the Queen (arrive), the audience (stand up).
21. You can’t go on vacation unless you (save) some money.
22. We can’t make any decision till he (arrive) here.
23. When winter (begin), the swallows will fly away to a warmer country.
24. Don’t count on a salary increase before you actually (get) it.
25. We (have) to stay on this desert island till we (repair) our boat.
26. When the fog (lift), we (be able) see where we are.
27. The refrigerator (go on) making that noise till we (have) it repaired.
28. As soon as the holidays (begin), this beach (become) very crowded.
29. The car (not move) till you (take) the brake off.
30. The alarm bell (go on) ringing till you press this button.
31. The band (start) playing as soon as everyone (arrive).
32. I (eat) dinner after I (finish) my homework
33. Call me as soon as you (get) in.
34. When he (return), I (give) him the key.
35. Stay here till the lights (turn) green.
Put the verbs in brackets into the correct tense (present or future).

Moscow is the capital of Russia. It is the main political, economic, educational and cultural centre of this country. Moscow is the seat of our Government. President of Russia lives and works there.

Moscow is situated on the Moskva river. The city was founded more than 800 years ago by Yury Dolgoruki.

There are many places of interest in our capital. The heart of Moscow is Red Square. The Moscow Kremlin and St. Basil's Cathedral are masterpieces of Russian architecture. For those who are fond of art the best place to visit is the Tretyakov Gallery or the Pushkin Museum of Fine Arts. The Gallery contains hundreds of masterpieces not only of Russian art but also of many other countries. Moscow is proud of the Bolshoi, Maly and Art theatres. Moscow is the scientific centre, too. The Academy of Sciences of Russia, the oldest university, many schools of higher education, colleges and scientific institutions are located there.

Environment - a set of components of the environment, natural and man-made natural objects and man-made objects.
Components of the environment - land, minerals, soils, surface and ground water, air, flora, fauna and other organisms, as well as the ozone layer of the atmosphere and near-Earth space, providing a set of favorable conditions for the existence of life on Earth.
Pollution - into the environment of matter and (or) energy, property, location or number of which have a negative impact on the environment.
Contaminant - a substance or mixture of substances, the number and (or) concentrations exceed established for chemical substances, including radioactive and other substances and microorganisms standards and have a negative impact on the environment.
Air pollution - a really serious problem. Air is composed of oxygen, nitrogen, water vapor, and, thanks to our civilization, of a variety of toxic particles. The more of these particles in the air is, the less room is left in the atmosphere for oxygen.
   The problem of air pollution is not limited to the space outside. The air inside our homes and offices can be as dangerous to your health. The main source of pollution - cigarette smoke, but it is not the only one. Toxins are allocated even when you just cook. Every time you scratch the Teflon non-stick coating is allocated enough toxins to kill a canary.
 Greenhouse effect, which we all have been associated with the phenomenon of global warming, caused by toxic gases. The main enemy of clear atmosphere - methane. It is released from the decomposition of sewage.
Greatly affects our waterways. In every neighborhood, in every city there drain sewer, storm water from the highways and municipal enterprises directly into the river. Everything goes into the water, passing minor cleaning steps.