Диагонали ромба ABCD пересекаются в точке О.Найдите углы треугольника AOB,если угол BCD=80 градусов.Помогите пожалуйста.

Чем внещнее строение папоротников отличается от строения хвощей и плаунов??

Задача:

Зрительный зал имеет 360 мест. Сколько осталось свободных мест после того,как 8 групп по 42 человека в каждой заняли свои места....

3.1 Are the underlined verbs right or wrong? Correct the verbs that are wrong. 1. Water boils at 100 degrees celsius. 2. The water boils. Can you turn it off? 3. Look! That man tries to open the door of your car. 4. Can you hear those people? What do they talk about? 5. The moon goes round the earth. 6. I must go now. It gets late. 7. I usually go to work by car. 8. 'Hurry up! It's time to leave.' 'OK, I come.' 9. I hear you've got a new job. How do you get on?

3.2 Put the verb in the correct form, present continuous or present simple. 1. Let's go out. It (not/rain) now. 2. Julia is very good at languages. She (speak) four languages very well. 3. Hurry up! Everybody --- (wait) for you. 4. '--- (you/listen) to the radio?' 'No, you can turn it off.' 5. '--- (you/listen) to the radio every day?' 'No, just occasionally.' 6. The River Nile --- (flow) into the Mediterranean. 7. Look at the river. It --- (flow) very fast today - much faster than usual. 8. We usually --- (grow) vegetables in our garden but this year we --- (not/grow) any. 9. 'How is your English?' 'Not bad. It --- (improve) slowly.' 10. Ron is in London at the moment. He --- (stay) at the Park Hotel. He --- (always/stay) there when he's in London. 11. Can we stop walking soon? I --- (start) to feel tired. 12. 'Can you drive?' 'I --- (learn). My father --- (teach) me.' 13. Normally I --- (finish) work at 5.00, but this week I --- (work) until 6.00 to earn a bit more money. 14. My parents --- (live) in Bristol. They were born there and have never lived anywhere else. Where --- (your parents/live)? 15. Sonia --- (look) for a place to live. She --- (stay) with her sister until she finds somewhere. 16. 'What --- (your father/do)?' 'He's an architect but he --- (not/work) at the moment.' 17. (at a party) Usually I --- (enjoy) parties but I --- (not/enjoy) this one very much. 18. The train is never late. It --- (always/leave) on time.19. Jim is very untidy. He --- (always/leave) his things all over the place.

3.3 Finish B's sentences. Use always ~ing . 1. A: I'm afraid I've lost my key again. B: Not again! You ----. 2. A: The car has broken down again.B: That car is useless! It --- 3. A: Look! You've made the same mistake again.B: Oh no, not again! I --- 4. A: Oh, I've left the lights on again. B: Typical! You ---

4.1 Are the underlined verbs right or wrong? Correct the ones that are wrong. 1. I'm seeing the manager tomorrow morning. 2. I'm feeling hungry. Is there anything to eat? 3. Are you believing in God? no I’m an atheist. 4. This sauce is great. It's tasting really good. 5. I'm thinking this is your key. Am I right?

4.3 Put the verb into the correct form, present continuous or present simple. 1. Are you hungry? Do you want something to eat? (you/want) 2. Jill is interested in politics but she --- to a political party. (not/belong) 3. Don't put the dictionary away. I --- it. (use) 4. Don't put the dictionary away. I --- it. (need) 5. Who is that man? What ---? (he/want) 6. Who is that man? Why --- at us? (he/look) 7. George says he's 80 years old but nobody --- him. (believe) 8. She told me her name but I --- it now. (not/remember) 9. I --- of selling my car. (think) Would you be interested in buying it? 10. I --- you should sell your car. (think) You --- it very often. (not/use) 11. I used to drink a lot of coffee but these days I --- tea. (prefer) 12. Air --- mainly of nitrogen and oxygen. (consist)

4.4 Complete the sentences using the most suitable form of be. Sometimes you must use the simple (am/is/are) and sometimes the continuous is more suitable (am/is/are being). 1. I can't understand why he's being so selfish. He isn't usually like that. 2. Jack --- very nice to me at the moment. I wonder why. 3. You'll like Jill when you meet her. She --- very nice. 4. Normally you are very sensible, so why --- so silly about this matter? 5. Why isn't Sarah at work today? --- ill?