Câu hỏi: 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 1: The big problem was that we really did not understand what was happened

A. problem

B. that

C. did not

D. was happened

Câu 2: Mercury and alcohol are widely used in thermometers because their volume increases uniform with temperature.

A. are

B. widely

C. their volume

D. uniform with

Câu 3: It is difficult to write rules that tell exactly when we should apologize, and it is not difficult to learn how to do it.

A. difficult

B. that

C. when

D. and

Câu 4: A beaver uses its strong front_teeth to cut down trees and peel_off its bark.

A. its

B. front teeth

C. eel off

D. its

Câu 5: The clerks who are happy to wait for their customer will get promoted soon.

A. clerks

B. wait for

C. customer

D. get promoted

Câu 6: The notion that students are not sufficiently involved in their education is one reason for the recently surge of support for undergraduate research.

A. notion

B. are not

C. their education

D. recently