Cho hệ phương trình: $\left\{ \begin{array}{l}{\rm{ax}} + y = 2\\6x + by = 4\end{array} \right.$. Có bao nhiêu cặp số nguyên $(a, b)$ để hệ phương trình vô nghiệm

Ứng dụng công nghệ nuôi cấy mô tế bào trong công tác giống

- 1 điều mấy đứa cảm thấy hạnh phúc, biết ơn.

- 1 thiếu sót mà bản thân cần cải thiện

- 1 điều mấy đứa muốn tìm hiểu hoặc 1

vấn để mà mấy đứa còn thắc mắc.

(Bằng tiếng Anh từ 5-10 câu. Mình đang cần gấp lắm)

*Choose the best answer to complete each of the following sentences

1.The Tsunami of December 2004 in south east asia…nearby areas and killed nearby 300,000 people

A.devastated B.struck

C.spoilt D.blocked

2.This ruler is…as long as that one

A.twice B.two

C.two times D.three times

3.Tom is very keen…languages

A.on learn B.at learn

C.on learning D.at learning

4.If more and more trees…,the climate…

A.die-changes B.will die-change

C.will die-will change D.die-will change

5.I haven’t decided…this summer

A.to spend my holidays where. B.where spend my holidays

C.where to spend my holidays D.to spend where my holidays

6.His friend…he would be back in an hour

A.spoke. B.told

C.said. D.wondered

7.”My watch has just broken”. -“Why don’t you…?”

A.have it repair B.childlike

C.childish D.childhood

8.I regret…school so young

A.leave. B.leaving

C.leaves. D.to leave

*Each sentence below contains an error.Uderline it and write the correct answer in the space provided

1.What will you do if you had an opportunity to travel on a spaceship

2.Peter is playing a computer game despite he has an exam tomorrow

3.They didn’t go to the theater last night and so didn’t we

*Use the correct form of the word given in each sentence

1.Don’t ask me.I’m really bad at making…(decide)

2.There are always interesting…at the big art museums in new york(exhibit)

3.This book provides information which is very…to us(value)

*Choose one word that does not belong to each group

1.A.Tamil. B.Islam. C.Hinduism. D.Buddhism

2.A.rose. B.lotus. C.bamboo D.orchid

3.A.season. B.decade. C.century D.timetable

4.A.typhoon. B.volcano. C.thunder. D.earthquake

5.A.aeroplane B.airhostess. C.spacecraft

D.helicopter

*Write complete sentence as directed

1.”Did i say that?”,Peter wondered(Change into reported speech)

—>

2.The girl turned out to be an old friend.I offered to carry her bag(Combine,using whose)

—>

*Rewrite each of the following sentences so that it has a similar meaning to the original one

1.”Do you like my new dress,John?”,asked Mary

—>Mary wanted

2.The garage repaired her car yesterday

—>She had

*Look carefully at each line.Some of the lines are correct,and some have a word which should not be there.Tick each correct line.If a line has a word which should not be there,write the word in the space

The authorities of Bangladesh are doing their best for the victims of the floods which have been covered many of low-lying coastal villages.The floods caused by a combination of very high spring tides and too heavy rainfall in the mountains,which according to government sources,could not to have been predicted.The government has called in the army to the affected areas,and they are handing out a food to the people who could have managed to get away from the flood by moving to more higher ground.The authorities estimate that there are must be several thousand people are in need of urgent medical attention.