Câu hỏi: Human beings are ________ greatest threat to survival of endangered species.

A. Ø

B. an

C. the

D. a

Câu 1: It was hot, _________ I turned on the conditioner.

A. however

B. but

C. because

D. so

Câu 2: Air pollution, together with littering, are causing many problems in our large, industrial cities today.

A. are

B. industrial

C. problems

D. with

Câu 3: The first color TV _____________ in 1928.

A. produce

B. is produced

C. was produced

D. produced

Câu 4: They_________ Ho Chi Minh City last summer.

A. visit

B. will visit

C. have visit

D. visited

Câu 5: It is of great ________ to show your interest and politeness when you are having a job interview.

A. important

B. importance

C. importantly

D. unimportant

Câu 6: If you eat too much, you _________ the price by putting on weight.

A. will pay

B. paid

C. would pay

D. were paying