11. a
12. b...............
21.4
1 is
2 is
3 is
4 is
, was
5 is
6 is
21.5
2 Where can I get some information (<em>uncountable) </em>about your country?
3 Let me give you a piece of advice. (<em>uncountable) </em>
4 Cook this spaghetti (<em>uncountable) </em>for ten minutes.
5 Can I have some bread (<em>uncountable)</em>, please?
6 Mary is looking for a new job (<em>countable</em>).
7 We should buy some new furniture (<em>uncountable)</em>.
8 The east of the country usually has_better weather (<em>uncountable) </em>than the west.
9. We went on two long trips (<em>countable) </em>last year.
10 I must find_new accomodation (<em>uncountable)</em> soon.
Present simple: Mr Brain builds the house.
Present continuous: Mr Brain is building the house at the moment.
Present perfect: Mr Brain has just built the house.
Present perfect continuous: Mr Brain has been building the house for 2 months.
Past Simple: Mr Brain built the house last year.
Past continuous: Mr Brain was building the house when I came.
Past Perfect: Mr Brain had built the house before he moved to Australia.
Past Perfect continuous: Mr Brain had been building the house for 2 months when his son was born.
Future Simple: Mr Brain will build the house soon.
Future Continuous: Mr Brain will be building the house tomorrow at 5 o'clock.
Future perfect: Mr Brain will have built the house by the end of September.
Future perfect continuous: Mr Brain will have been building the house for 2 months already by the end of September.
1. Yes, I like history.
2. The period of the Middle Ages is more interesting for me and I would like to live in it.
3. Many events in history changed the face of the world. For example: the epoch of geographical discoveries, the First World War, the Second World War, many revolutions in different countries and etc.
4. I can name some people: Napoleon Bonaparte, Adolf Hitler, V. I. Lenin and others.
5. To my mind, in nowdays there is a threat of a third world war, but I hope that it never comes.
6. The greatest problems in nowdays are: polution of environment, a threat of world war and etc. We саn solve the problem of polution. Every man should not litter, industrial enterprises must install purifying facilities.