câu 3 không chắc

III. REWRITE THE FOLLOWING SENTENCES AS DIRECTED

1. Mary was sick.She didn’t leave the meeting until it ended.

Despite ………being sick, Mary didn’t leave the meeting until it ended……..

2. We live in the same street. We rarely see each other.

Inspite of……living in same street,we rarely see each other.……….

3. Despite her richness, she is not happy.

Although……………… being very richness, she isn't happy………………..

112446+398=112835

3975-576=3408

478+38710=39188

* Write the second sentence so that it has the same meaning as the first one.
1. When did you buy your motorbike?
How long …………………have you bought your motorbike? …………………
2. Everyone must respect the traffic laws. 
The traffic ……………… laws must be respected by everyone………………………
3. The town council has created a cooking club.
A cooking …………………club has been created by the town council…………………………
4. Living in a village always seems strange to me.
I have never ………… lived in village before…………………………
5. I didn’t switch the computer off when I went out. 
I forgot ………………… to switch the computer off when i went out…………………
6. It’s not possible to play tennis because of the rain.
The rain makes ………………it impossible to play tennis.……………………………
7. Unless you leave home now, you will miss the flight.
If ……………he doesn't hurry, he will miss the show.……………………………
8. “Did you write a note for Anna?” I asked my mother.
I asked ………… my mother whether/if she had written a note for Anna.……………………………
9. Sue had left the office before the manager arrived there.
When the manager …………………arrived at the office Sue had left…………………
10. If I were you, I would check my answers before handing in the test.
You had ……………… better check your answers handing in the test………………………………………

nH2 = 6,72/22,4 = 0,3 mol

X + 2HCl -> XCl₂ + H₂

=>n_X=n_H2=0,3 mol

=>M_X=7,2/0,3=24

=>X là Mg

tham khảo: https://hoidapvietjack.com/q/648/cho-83-g-hon-hop-a-gom-3-kim-loai-dong-nhom-va-magie-tac-d

EXERCISE 10: Rewrite the following sentence using passive voice.

1. We export this computer to seventy different countries. 

this computer is exported to seventy different countries

2.We have invited all the students in the school.

all the students have been invited in the school

3. They posted all the letters yesterday. 119 Thầ y Bùi Văn Vinh – 0988.333.599

All letter were posted yesterday.

4. The police found two children in the forest.

Two children were found in the forest by the police.

5. Mary is cutting the cake with a sharp knife.

A cake is being cut with a sharp knife by Mary.

6. The teacher is going to tell a story.

 a story is going to be told by the teacher

7. An earthquake destroyed the town.

The town was destroyed by an earthquake

8. He didn’t type the letter last night.

The letter wasn’t typed last night

9. My father will take me to Ho Chi Minh City next week.

 I will be taken to Ho Chi Minh City by my father next week

10. A man returned the keys to me.

 The keys was returned to me by a man

1. Why didn't they help him?

why wasn't he helped?

2. How many games has the team played?

how many games have been played by the team?

3. Where do people speak English? 118 Thầ y Bùi Văn Vinh – 0988.333.599

where is english spoken

4. Who are they keeping in the kitchen?

who is being kept in the kitchen?

5. How can they open this safe?

how can this safe be opened?

6. What books are people reading this year?

what books are being read this year?

7. How did the police find the lost man?

how was the lost man found by the police?

8. Who look after the childen for you?

who are you looked after the children by>?

9. How long have they waited for the doctor?

How long has the doctor been waited?

10. What time can the boys hand in their papers?

what time can their papers be handed by the boys?

gọi A=111...1 ( 27 chữ số 1)
Có A= 111..100..0( 9 chữ số 1 và 18 chữ số 0 ) + 111..100..0 ( 9 chữ số 1 và 9 chữ số 0 ) + 111..11 ( 9 chữ số 1)
=11..1 x 10⁸ + 11..1 x 10⁹ +11..1
= 11..1 x ( 10⁸ + 10⁹ + 1)
Vì 11..1 có 9 chữ số
=> tổng các chữ số =9 chia hết cho 9 nên 11..1 chia hết cho 9
(10^8 + 10^9 + 1) có tổng các chữ số bằng 3 nên chia hết cho 3
=>A= 9k. 3k' = 27kk'
=> A chia hết cho 27