Câu hỏi: Passengers are required to arrive to the gate fifteen minutes before departure time.

A. are required

B. to arrive to

C. before

D. departure time

Câu 1: When a lion gets hungry, its manner changes and it becomes threatened.

A. when

B. its manner 

C. and

D. threatened

Câu 2: I can’t find the letter I received from my boss some days ago. I might throw it into the waste paper bin yesterday.

A. received

B. can’t find

C. into the

D. might throw

Câu 3: Little have people done to alleviate the sea pollution caused by the factories in central Vietnam, haven’t they?

A. have people done

B. caused

C. in central

D. haven’t they

Câu 4: It is believed that in the near future robots will be used to doing things such as cooking.

A. it is believed

B. in the near future

C. be used to cooking

D. such as

Câu 5: By measuring the color of a star, astronomers can tell how hot is it.

A. measuring

B. the

C. how

D. is it

Câu 6: There are many different ways of comparing the culture of one nation with those of another.

A. There are

B. of comparing

C. those

D. another