引力是拉力还是推力?爱因斯坦说是推力那为什么现在教科书没有说明这点?

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引力是拉力还是推力?爱因斯坦说是推力那为什么现在教科书没有说明这点?
引力是拉力还是推力?
爱因斯坦说是推力那为什么现在教科书没有说明这点?

引力是拉力还是推力?爱因斯坦说是推力那为什么现在教科书没有说明这点?
推力

Lesson 16
A
1 It is an English car.
2 It is a Japanese car.
3 It is an Italian car.
4 It is a French car.
5 It is an American car.
6 Robert is not a teacher.
B
1 Wh...

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Lesson 16
A
1 It is an English car.
2 It is a Japanese car.
3 It is an Italian car.
4 It is a French car.
5 It is an American car.
6 Robert is not a teacher.
B
1 What colour are your shirts? Our shirts are white.
2 What colour are your coats? Our coats are grey.
3 What colour are your tickets? Our tickets are yellow.
4 What colour are your suits? Our suits are blue.
5 What colour are your hats? Our hats are black and grey.
6 What colour are your passports? Our passports are green.
7 What colour are your umbrellas? Our umbrellas are black.
8 What colour are your handbags? Our handbags are white.
9 What colour are your ties? Our ties are orange.
10 What colour are your dogs? Our dogs are brown and white.
11 What colour are your pens? Our pens are blue.
12 What colour are your cars? Our cars are red.
Lesson 18
A
1 That man is tall. He is a policeman.
2 Those girls are busy. They are keyboard operators.
3 Our names are Britt and Inge. We are Swedish.
4 Look at our office assistant. He is very hard-working.
5 Look at Nicola. She is very pretty.
6 Michael Baker and Jeremy Short are employees. They are sales reps.
B
1 Are they keyboard operators or air hostesses?
They aren't keyboard operators. They're air hostesses.
2 Are they postmen or policemen?
They aren't postmen. They're policemen.
3 Are they policewomen or nurses?
They aren't policewomen. They're nurses.
4 Are they customs officers or hairdressers?
They aren't customs officers. They're hairdressers.
5 Are they hairdressers or teachers?
They aren't hairdressers. They're teachers.
6 Are they engineers or taxi drivers?
They aren't engineers. They're taxi drivers.
7 Are they policewomen or keyboard operators?
They aren't policewomen. They're keyboard operators.
8 Are they milkmen or engineers?
They aren't milkmen. They're engineers.
9 Are they policemen or milkmen?
They aren't policemen. They're milkmen.
10 Are they nurses or housewives?
They aren't nurses. They're housewives.
Lesson 20
A
1 Those children are tired.
2 Their mother is tired, too.
3 That ice cream man is very busy.
4 His ice creams are very nice.
5 What's the matter, children? We are thirsty.
6 What's the matter, Tim? I am tired.
Answers
B
1 Are the children tired or thirsty? They're not tired. They're thirsty.
2 Are the postmen cold or hot? They're not cold. They're hot.
3 Are the hairdressers thin or fat? They're not thin. They're fat.
4 Are the shoes small or big? They're not small. They're big.
5 Are the shops shut or open? They're not shut. They're open.
6 Are his cases heavy or light? They're not heavy. They're light.
7 Are grandmother and grandfather young or old? They're not young. They're old.
8 Are their hats old or new? They're not old. They're new.
9 Are the policemen short or tall? They're not short. They're tall.
10 Are his trousers short or long? They're not short. They're long.
Lesson 22
A
1 Is this Nicola's coat? No, it's not. Her coat is grey.
2 Are these your pens? No, they're not. My pens are blue.
3 Is this Mr. Jackson's hat? No, it's not. His hat is black.
4 Are these the children's books? No, they're not. Their books are red.
5 Is this Helen's dog? No, it's not. Her dog is brown and white.
6 Is this your father's tie? No, it's not. His tie is orange.
B
1 Give me a cup please. Which one? This ditty one? No, not this dirty one. That clean one. Here you are. Thank you.
2 Give me a glass please. Which one? This empty one? No, not this empty one. That full one. Here you are. Thank you.
3 Give me a bottle please. Which one? This large one? No, not this large one. That small one. Here you are. Thank you.
4 Give me a box please. Which one? This big one? No, not this big one. That little one. Here you are. Thank you.
5 Give me a tin please. Which one? This new one? No, not this new one. That old one. Here you are. Thank you.
6 Give me a knife please. Which one? This sharp one? No, not this sharp one. That blunt one. Here you are. Thank you.
7 Give me a spoon please. Which one? This new one? No, not this new one. That old one. Here you are. Thank you.
8 Give me a fork please. Which one? This large one? No, not this large one. That small one. Here you are. Thank you.
Lesson 28
A
1 There are some pencils on the desk.2 There are some knives near that tin.
3 There are some policemen in the kitchen.
4 There are some newspapers in the living room.
5 There are some keyboards operators in the office.
B
1 Are there any books in the room?
No, there aren't any books in the room.
There are some magazines.
Where are they?
They're on the television.
2 Are there any ties on the floor?
No, there aren't any ties on the floor.
There are some shoes.
Where are they?
They're near the bed.
3 Are there any glasses on the cupboard?
No, there aren't any glasses on the cupboard.
There are some bottles.
Where are they?
They're near those tins.
4 Are there any newspapers on the shelf?
No, there aren't any newspapers on the shelf.
There are some tickets.
Where are they?
They're in that handbag.
5 Are there any forks on the table?
No, there aren't any forks on the table.
There are some knives.
Where are they?
They're in that box.6 Are there any cups on the stereo?
No, there aren't any cups on the stereo.
There are some glasses.
Where are they?
They're near those bottles.
7 Are there any cups in the kitchen?
No, there aren't any cups in the kitchen.
There are some plates.
Where are they?
They're on the cooker.
8 Are there any glasses in the kitchen?
No, there aren't any glasses in the kitchen.
There are some bottles.
Where are they?
They're in the refrigerator.
9 Are there any books in the room?
No, there aren't any books in the room.
There are some pictures.
Where are they?
They're on the wall.
10 Are there any chairs in the room?
No, there aren't any chairs in the room.
There are some armchairs.
Where are they?
They're near the table.
Lesson 40
A
1 Send that letter to George.
2 Take those flowers to her.
3 Show that picture to me.
4 Give these books to Mrs. Jones.
5 Give these ice creams to the children.
B
1 I'm going to put it on.
2 I'm going to take them off.
3 I'm going to turn them on.
4 I'm going to turn it off.
5 I'm going to put it on.
6 I'm going to take it off.
7 I'm going to turn them on.
8 I'm going to turn it off.
9 I'm going to turn them off.
10 I'm going to turn it on.

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爱因斯坦的引力理论是时空弯曲所造成的.是时空的一个属性,牛顿的万有引力是理论上是吸力!

你只需要明白引力是由于时空扭曲而产生的就可以了。教科书是不会解释引力这一高深问题的,就像是摩擦力。

我认为是拉力 引力是一种互相吸引的力量

当然是拉力了,你跳一下试试什么感觉,如果是推力你一跳就上月球了

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