Задайте вопрос не так ли не правда ли к предложению some of the best russian paintings are in the tretyakov gallery

Some of the best Russian paintings are in the Tretyakov Gallery, aren't they?

Упр1
1.Jack has washed te dog.
2. Father has cleaned his car.
3.The boys have bought some sweets.

Упр2
1. They haven't painted their old house.
2. She hasn't broken a vase.
3. We haven't cleaned the room.

Упр3
1. Has the train  arrived?
2. Have you worked here for a long time?
3. Has Kavin phoned his friend?

Упр4
1. We have just phoned the doctor. 
2. The train hasn’t arrived yet.
3. The cat already has eaten up the fish. 
4. Have you washed your hands yet? 
5. We have just met an American actor. 

Упр5
1. I’ve lived in Moscow since1997.
2. Ben has studied English for three years.
3. They haven’t visited their grandparents  for months.
4. Julie’s ill. She’s been in bed since Tuesday.
5. We have moved to Oxford since I was ten.

Упр6
Dear Mum and Dad,
I’ve lived in Africa for two weeks and I love it! Africa is beautiful! I haven’t travelled to any faraway place since last summer. I’m so happy now!
I’ve already seen Mr. Rambler. He is working for WWF here and taking photos of wild animals. I haven’t seen any lions yet. I think I’ll see them later.
Thank you for the trip. I’ve dreamed of Kenya since my childhood. I haven’t seen you for a long time! I miss you so much!
Love, Nigel.

1 с
2 с
3 a
4 с
ll.
1) The Bahamas are a group of islands in the Atlantic Ocean
2)  I started on the Black sea ,then went round Bulgaria ,Greece , Iitaly , France and many other countries
3)The capital of USA is Washington , though some people think it is New York.
4). Tokyo is the largest city in the world.
5). The Volga runs into the Caspian sea.
6). The Pacific ocean is very deep.
7).  Kazbek is the highest peak of the Caucasus montains. 
8).  I have never been to lake Onega.
9).  Washington is the capital of the United States.
lll
1 were
2 would give
3 were
4 had phoned
5 hadn't invented
6 could
7 wouldn't dry out
8 had followed