Câu hỏi: 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 1: 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 2: These snakes will not cause you any serious harm. They are harmful.

A. snakes

B. cause

C. harm

D. harmful

Câu 3: By the turn of the century, most of the inventions that were to bring in all the comforts of modern living has already been thought of.

A. By the turn of

B. that

C. were to

D. has already been

Câu 4: 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

Câu 5: The Red Cross organizes and leads relief assistance missions after natural disasters such as floods, tsunamis, earthquakes, and homelessness.

A. The Red Cross

B. organizes and leads

C. assistance missions

D. and homelessness

Câu 6: There was a gradual raise in the number of literate males and females in the lowlands.

A. a gradual

B. raise

C. literate

D. the lowlands