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: 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 2: Ours brains are incredibly agile machines, and it's hard to think of anything they do more efficient than recognize face.

A. are

B. anything

C. efficient

D. recognize

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: Doctors believe there is better in this modern world of ours to try to prevent illnesses than to rely on medicines to cure them.

A. doctors

B. there is

C. of ours

D. to

Câu 5: 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 6: Species like snakes, lizards, coyotes, squirrels, and jack rabbits seems to exist quite happily in the desert.

A. like

B. seems to

C. quite happily

D. the