Колесо радиусом 50 см вращается с частотой 1200 об/мин. Какова линейная скорость точек, расположенных на ободе колеса?

союз это часть речи?

Раскройте скобки, заменяя инфинитив нужной формой глагола-сказуемого. 1. "You ­­­____________(to see) the new pictures by Andrew?" "Yes" "How you____________ (to like) it?" "I like it very much" 2. "You ever ____________ (to be) to England?" "Yes", I ____________ (to go) there last winter". 3. "Is Nick at home?" "No, he ____________ (not to come) yet". 4. I just____________ ( to finish) work and___________ (to read) a book now. 5. "Where's your sister?" "She____________ (not to come) home from school yet. I think she still ____________ (to play) tennis" 6. "You____________ (to do) the translation already? You only _____________ (to begin) it 20 minutes ago". 7. "You ________ (to finish) the work yet" Cant have a look at it?" "Certainly. I _____________ (to finish) it an hour ago". 8. "When you ____________ (to come) to Moscow?" "A week ago".

В классе списал с тетрадки друга которую она уже проверила и поставила ему правильные ответы вот они:

1. Saw, like

2. Been.

3. has come

4. finished, read

5. come, play has not come, has played

6. done, begun

7. Finished, finished,

8. come have come

Но когда сдал я она сказала что это не правильно.

Еще есть одно упражнение там уже наверняка я правильно списал, с готовой тетради но училка отметила как не правильное:

Задание 5. Закончите предложения, используя since или for. Let's visit Aunt Emily. (Christmas) We haven't visited her since Christmas. 1. Let's invite Harry and Jane to dinner________.(March) 2. Let's play cards with the Kents________. (Weeks) 3. Let's walk round the park________. (Years) 4. Let's watch TV________. (last Friday) 5. Let's hear an opera________. (Month) 6. Let's phone our parents________. (Two weeks) Mike is ill.(for a week) He has been ill for a week. 1. My brother is married________. (For two years) 2. I know Steve________. (Since I was a child) 3. Nick is absent________. (For a week) 4. Jack lives in London________.(since he was born) 5. Mr Morgan is away ________ (for two month) 6. Bill is unemployed________. (Since April) 7. Ann has a bad cold________ (for the last few days) 8. Trie shop is open ________ (since 8 o'clock)

Написал:

сравните строение атомов калия с массовыми числами 39 и 40.

когда были изобретены самые ранние орудия труда?