Cho O là trọng tâm của tam giác ABC chứng minh rằng vecto \(\overrightarrow{OA}+\overrightarrow{OB}+\overrightarrow{OC}=0\)

Cho 6 điểm ABCDEF hãy tĩnh tổng \(\overrightarrow{AB}=\overrightarrow{BC}\) _,\(\overrightarrow{AD}+\overrightarrow{BE}+\overrightarrow{CF}\)

ABCD hình bình hành M,N trung điểm BC , AD chứng minh rằng \(\overrightarrow{AM}+\overrightarrow{AN}=\overrightarrow{AB}+\overrightarrow{AD}\)

Ex Rewrite the following sentence using passive voice

1 She looked after our children when we were out .

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2 Nobody has used this room for ages .

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3 The boy hit the dog in the garden yesterday.

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4 Who wrote this book ?

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5 Who has cleaned this room ?

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6 The fire has caused considerable damage .

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7 The committee is considering several new proposals .

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8 No one may open this letter , may they ?

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9 They bought her a present on her birthday

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10 Someone has told him to report for duty at 6.00pm

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11 The author has written a special edition for children .

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12 They make these artificial flowers.

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13 Does John return the book he borrowed yesterday?

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14 They are pulling down the old theatre .

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15 We use this room onlyon special occasions .

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Ex Rewrite the following sentence using passive voice

1 They built this church in 1973

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2 Do they teach English in your school ?

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3 Nobody believes his story

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4 Someone is following her

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5 They asked me many difficult questions.

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6 They are repairing my piano

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7 They are building a house , aren't they ?

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8 Students are doing a lot of homework

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9 Can Mary tear the letter ?

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10 Do you understand this lesson ?

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Ex Rewrite the following sentence using passive voice

1 The keepers wre feeding the lions=>........................................................

2 They have taken her to the hospital=>.......................................................

3 They had fastened his whole body to the ground =>.............................................................

4 The school boys had wasted a lot of time=>.......................................................................

5 We write letter to our friend once a week =>.......................................................................

6 We clean the garages everyday=>....................................................................

7 Someone has given him a lot of money =>....................................................................

8 The police arrested two hundred people =>............................................................................

9 We export this computer to seventy different countries=>.........................................................

10 They have cancelled the meeting =>...............................................................................

Ex : Rewrite the following sentence using passive voice

1 My father waters this flower every morning=>............................................................

2 A stone broke the window =>...........................................................................

3 The servants didn't do the work => .......................................................................

4 She often takes her dog for a walk =>........................................................................

5 The army will complete that project next year =>........................................................

6 They won't punish him =>...............................................................................

7 People don't use this road very often= >...........................................................

8 the manager always welcomes new employees=> ............................................

9 We are following them =>...........................................................................

10 The airplanes are dropping booms =>..............................................................

Ex Choose the best answer to complete the following sentenses

1'' We are still looking for Thomas .'' ''Hasn't he ...........................yet?

A been found B to find C found D being found

2 You .......................by my secretary next week

A will notify B would notify C will be notified D is going to notified

3 The wheel .......................thousands of years ago

A invented B has invented C is invented D was invented

4 I still can't believe it . My bike ...........................last night

A was stolen B was stealing C stolen D stole

5 today , many serious childhood diseases .............................by early immunization .

A are preventing B can prevent C Prevent D can be prevented

6 Kieu story.................................by Nguyen Du hundreds years ago

A is written B has been written C wrote D was written

7 The questions ...........................by the students at the moment .

A are discussed B will be discussed C have been discussed D are being discussed

8 Many people ...............................killed in the accident last night

a had been killed b were killed C killed D being killed