1Who invited her to the party?  => By whom was her invited to the party

          -  The party be invited  by who ? 

           - The party  was invited by whom ? 

           - By whom the party was invited ? 

          -  By whom was the party  invited? 

2 When did they buy this car? 

When was this car bought?

3 Was Mary helping her mother in the kitchen? 

Was her mother being helped by mary in the kitchen

4 Will you invite her to your birthday party? 

Will she be invited to your birthday party?

 5  He cleans the house 

The house is cleaned by him

6 He is cleaning the house 

The house is being cleaned by him

 7 He has cleaned the house 

THe house has been cleaned

  8  He cleaned the house 

THe house was cleaned by him

 9 He was cleaning the house 

THe house was being cleaned by him

 10 He had cleaned the house 

The house had been cleaned by him

11 He should clean the house 

THe house should be cleaned by him

12  He will clean the house 

THe house will be cleaned by him

Chuyển câu chủ động thành câu bị động

Who has just cleaned the floor

➞ who has the floor been cleaned by?

➞by whom has the floor been cleaned?

Who must water the flower

➞who must the flower be watered by?

➞by whom must the flower be watered

Who helps you everyday

➞who are you helped everyday by?

➞by whom are you helped everyday?

Chuyển từ câu chủ động -> bị động

1.Who helped her?

-->By whom ...............was she helped................?

2.Who bake this cake?

-->By whom ...............is this cake baked............?

3.Who has written this sentence on the wall?

-->By whom ...............has this sentence been written on the wall................?

sao lại dùng whom mà ko phải who 

giải thích đc ko ạ

Chuyển từ câu chủ động -> bị động

1.Who helped her?

-->By whom she was helped ?

2.Who bake this cake?

-->By whom this cake is baked?

3.Who has written this sentence on the wall?

-->By whom this sentence has been written on the wall ?

sao lại dùng whom mà ko phải who 

giải thích đc ko ạ

Chuyển từ câu chủ động -> bị động

1.Who helped her?

-->By whom was she helped?

2.Who baked this cake?

-->By whom was this cake baked?

3.Who has written this sentence on the wall?

-->By whom has this sentence on the wall been?

Who was the radio invented ?

By whom was the radio invented?

1. My father takes me to school everyday

2. A large number of people read this book

3. The citizens warmly welcome the President

4. Jim invites you to the party

5. Many children love chocolate

6. The authorities protect historic places in my hometown

7. The old man's grandchildren visit him regularly

8. I accidentally tear the letter

9. My teacher clearly explains this problem

10. My mother places the vase under the table.