Câu hỏi: We had better to review this lesson carefully because we will have some questions on it.

A. to review

B. carefully

C. will have

D. on

Câu 1: The developing of the submarine was hindered by the lack of a power source that could propel an underwater vessel.

A. developing

B. the

C. a power

D. could propel

Câu 2: The sates school system in England can be divided into two levels of educated: primary and secondary

A. be divided

B. into

C. educated

D. secondary

Câu 3: The big problem was that we really did not understand what was happened

A. problem

B. that

C. did not

D. was happened

Câu 4: These snakes will not cause you any serious harm. They are harmful.

A. snakes

B. cause

C. harm

D. harmful

Câu 5: The office manager insists that his staff use all of their vacation time, but he hardly never takes a vacation himself.

A. insists

B. use

C. their

D. hardly never

Câu 6: The clerks who are happy to wait for their customer will get promoted soon.

A. clerks

B. wait for

C. customer

D. get promoted