6,02 x 1024 молекулам карбонатної кислоти H2CO3; відповідає кількості речовини: А. 5 моль;
Б. 10 моль;
В. 15 моль;
Г. 20 моль.​

1. Is it your responsibility to serve the customers as quickly as possible in this shop?

2. If you’re a coal miner, you don’t have to deal with the public at all.

3. I hate it when I have to use a computer for work.

4. Famous footballers earn more money from advertising than from playing football.

5. Nobody wants to be in charge of the marketing office.  

6. We do manual work and we like it – it’s quite rewarding.

7. It is my job to answear the phone when customers call with questions.

8. I'm the manager of a large team so I have to supervise lots of people.

I don't think that it's important to study Russian language for teenagers from other countries, but it may be useful. They'll be able to communicate with Russians. And that's all... because of it I think that knowing Russian language not that important for teenagers from other countries. 
Я не думаю, что изучать Русский язык так важно для подростков из других стран, но это может быть полезно. Они смогут общаться с русскими. И это всё... из-за это я думаю, что знание Русского языка не так важно для подростков из других стран.

Как-то так :/