7.14 Put the verbs in brackets into the Present Simple, the Present Continuous, the Present Perfect or the Present Perfect Continuous Tense.
1) ... you ... (to go) to the concert next Sunday, Julia? — Yes. Actually I ... (already to buy) a
ticket. I never ... (to miss) an opportunity to visit concerts of famous singers and music bands. 2) ... Alan ... (to check) his e-mail yet? — Yes, he ... . He always ... (to read) his mail in the morning. 3)... you ... (to wait) for a bus? How long ... you ... (to wait) for it? — I ... (to wait) for half an hour already.— How strange. It usually ... (to arrive) on time. 4) ... Jessica still ... (to be) in the fitting
room? She ... (to try) clothes on for hours! — Well, she seldom ... (to go) shopping for clothes, but
if she does, she ... (to spend) hours choosing dresses and blouses. Look! She ... (finally to choose) what to buy.
5)... you still... (to work) on the computer, Mark? You ... (to work) since 8 o’clock.— I... (to look) for some information for my Biology project for three hours already but I can’t find anything interesting. It always ... (to take) a lot of time to find necessary information on the Net.
6)... Mr Peters still ... (to work) at school? — Yes, he ... (to teach) Maths for twenty years. He ... (to be) a very good teacher, you know.
7) What ... Tina ... (usually to do) in the evenings? I never ... (to see) her walking with her friends.— She ... (toprepare) for her final tests these days. She ... (to want) to enter University and she really ... (to study) hard since the beginning of the school year.
8) Where ... you ... (to hurry) now, Sue? — I... (to have) a seminar at the University today. It ... (to start) in half an hour.
9) Why ... Gordon ... (to read) the newspapers since morning? — He ... (to want) to find a part-time job for summer. You know, he ... (already to decide) to buy a new computer and he ... (to need) money for it.
10)... you already ... (toplan) your trip to France? — Yes,
we ... . We ... (to fly) to Paris tomorrow morning. Richard ... (already to buy) tickets and Helen ... (to pack) suitcases since 10 o’clock.

1. Процесс преобразования веществ в другие вещества-это очень важно.
2. Существует множество причин, чтобы изучать химию.
3. То получить соли вы должны знать некоторые получения солей.
4. Можно получить хорошие знания химии, изучая теоретическую химию и переноски 
к выполнению практических работ. 

Образец выполнения:
Лучший определить 
количество материала в пробе 
твердого тела является вес его на баланс. 
чтобы определить - инфинитив в функции определения
взвесить - инфинитив в функции составной части глагольного сказуемого

 My Working Day  Мой рабочий деньI want to say that all weekdays except weekends look very much the same.On weekdays the alarm clock wakes me up at about 7 o'clock and my working day begins. I'm not an early riser that's why it's very difficult for me to get out of bed, especially in winter. I switch on my tape-recorder and do my morning exercises. Then I go to the bathroom, take a warm shower and clean my teeth. After that I go to my bedroom to get dressed.Я хочу сказать, что все дни недели, за исключением выходных, похожи друг на друга.В будние дни мой рабочий день начинается рано утром. Я не люблю рано вставать, но привык. Обычно я встаю около семи часов. Затем я делаю зарядку (но не каждый день!), потом иду в ванную комнату, чтобы умыться и почистить зубы. At a quarter past seven I am ready to have my breakfast. As a rule, 1 have a quick light breakfast which consists of a cup of coffee or tea, a boiled egg, and a cheese or a sausage sandwich. After breakfast I take my bag and leave for school.As my school is not far from my house, it takes me 10 minutes to get there. I usually walk there.Six or seven lessons a day is the ordinary timetable. The classes at school are over at about three o'clock. Twice a week I stay at school later to play tennis or I am busy with the English language club.В четверть восьмого я готов завтракать. Как правило, у меня быстрый легкий завтрак, который состоит из чашки кофе или чая, вареного яйца и бутерброда с сыром или колбасой. После завтрака я одеваюсь, беру портфель и иду в школу.Так как школа недалеко от дома, мне нужно десять минут, чтобы добраться туда. Обычно я иду пешком.Шесть или семь уроков в день — обычное расписание. Уроки в школе заканчиваются около трех. Два раза в неделю я задерживаюсь в школе, чтобы поиграть в теннис или занимаюсь в английском клубе.When I come home I have lunch, after lunch I have a rest. While resting, I listen to the music or look through the newspapers and magazines. Then I start doing my homework. It takes me about five hours to cope with my homework properly. Sometimes I help my mother about the house and do our shopping, go to the library and have private lessons in English in order to improve it.After dinner I usually relax for some time and then go on with my homework.As a rule, I go to bed at about 11 o'clock or even later.