3. a) fill in the gaps in the sentences using the words in the oval. watch out! there is an extra word.engine, foresaw, helicopter, balloon, vehicle, powered, aeroplane, machines, appeared, invention- это слова которые нужно вставитьin the 14-th century leonardo da vinci the possibility of the man-made and man-made .man started with the non-power-driven . a hot air was the first to lift man from the surface of the earth. then there winged heavier-than-air craft. yet, the achievement of man-directed flight came with the . the first flight in a man-carrying aerop1ane was made by a.f.mozhaisky in 1884.

Teenagers all across the world enjoy different activities in their free time.  sport plays a great role in russian teenagers' lives. we are  connected with sport since our childhood, though we don’t even notice this fact, because we start to play different  games outdoors even when we are just 4-5 years old. many people go to arts school and take painting classes or learn how to play piano or violin. for example, there are a lot of people in my school who chose this type of activity. on the other side, some teenagers spend their time on useless things, like playing computer games and chatting online. but there's nothing we can do about it. moreover, you are easily addicted to this type of spending your time when you start doing it. some people say that they like to learn foreign languages. others say that they like reading books or enjoy leisure time with their friends and families. in fact, any type of leisure activity is fine - as long as it doesn't hurt you and as long as you enjoy it

Many things have changed over the past decades. same can be said about the life of modern teenagers. today teens are more independent, have other interests, and are definitely lazier than before. computer is the root of most changes in the society. modern teenagers spend almost all their free time online, playing computer games, chatting with friends, surfing social networks, instead of going out and doing some outdoor activities. if you ask a teenager what the life was like twenty or thirty years ago, he won’t answer, because he doesn’t know. modern children simply can’t imagine their life without cell phones, tablets and mp3 players. these gadgets have gradually replaced the whole world of childish games and live communication. previous generations of teenagers could still be seen in the streets jumping, running around and playing active games. today, teenagers are mostly seen online. from the one hand, it’s certainly not good. from the other hand, this can be understood. how can children avoid electronic toys if they are everywhere? other than that, the life of teenagers is not easy. they have a number of problems, which they don’t want to discuss with adults. chatting with friends, at least they can share with them. being online, they can also find answers for many urgent questions or problems. modern teenagers are luckier than other generations for having the freedom of choice and life full of possibilities. it’s a “computer-based” generation. even their homework is done with the help of computers and the interne