Упражнение 1. Поставь глагол в скобках в Present Perfect или Present Perfect Continuous. 1. We (to do) our lessons since breakfast.
2. They (not to hear) about him for a long time.
3. She (to drive) since she was 18.
4. John (to fail) his test three times because he doesn't know how to park.
5. Andrew (not/pass) his driving test because he doesn’t know the rules well.
6. She (worry) about this for three weeks.
7. She (study) History for hours every day.
8. She (not to see) him for ages.
9. They (not/take) another test yet.
10. She is my friend, I (to know) her for a long time.
11. Tom has a stomachacke. He (to eat) junk food all day.
12. I (never to hear) that song before.

Dear Bob (Name),
I love reading the letters you send me. Thank you for being so caring and sincere. I am sure your cat will be alright.
Regarding your questions, it is clear that pets need time and attention that some people might not be able to provide. And it is such a big responsibility! It is basically a baby that is never growing older. I approve of keeping exotic pets you mentioned, as spiders and snakes are far from exotic, however, if it is a huge animal that cannot adapt to another environment, then clearly it is animal abuse. Russia is not that different from other European countries. I would say cats and dogs are in the majority. Parrots, however, are rarely kept as pets. Well obviously, because of the weather.
Sincerely,

Hi, Ben. Thanks for your long and interesting letter. It was pleasure for me to hear you after not hearing you for ages. Sorry that I did not write earlier but I was very busy.
I think that people do not want to have pets because the afraid of responsibility on them. You have to feed your pet, comb his hair and other. No, I do not like snakes or spider. They are very horrible for me. I prefer cats or dogs which are the best friends for me. There are a lot of popular pets in my country such as dogs, cats, turtles and otheres, too. 
This is everything what I wanted to say about.
Love,
your friend.