1. В том, что мы не ставим перед ним вс глагол don't/doesn't, а используем отрицательную форму глагола (с частицей not).
I am not a doctor [не I don't be a doctor/I don't am a doctor]
We are not doctors [не We don't be a doctor/We don't are a doctor]
He is not a doctor [не She doesn't be a doctor/She doesn't is a doctor]
2. Так же - мы не ставим вс глагол do/does на начало предложения, но ставим одну из форм глагола to be (в зависимости от лица).
Am I a doctor? [не Do I be a doctor?/Do I am a doctor?]
Are we doctors? [не Do we be doctors?/Do we are doctors?]
Is he a doctor? [не Does he be a doctor?/Does he is a doctor?]
3. always (всегда), often (часто), every day (каждый день), every year (каждый год), every week (каждую неделю), usually (обычно), sometimes (иногда), seldom (редко) (подробный список можно посмотреть в Интернете)
1. Did you hear what I told you, or do you want me to repeat again?
2. Can I go now or do you want me to stay?
3. No one noticed how calmly he fell asleep.
4. He wants to be sent to a conference in Moscow.
5. He felt the wind burst through the window and mixed papers on his desk.
6. Can you practice making this difficult sound?
7. It is best to avoid traveling around New York during rush hours. You can get stuck in traffic.
8. I want to eat something tasty. Do you mind if I make dessert?
9. John tried to postpone his homework for later. But mom insisted that he do it immediately.
10. Mom is used to decorating dishes when she sets the table. Everything looks very beautiful.
11. Unaware of the danger, we continued on.
12. Finding out that he was still in Moscow, I called him.
13. Having read many books on this subject, he was able to talk about it for hours.
14. The secretary sent letters signed by the director.
15. When working, I always listen to music.
