Câu hỏi: Choose the correct answer to fill in the blank. 

A. that are

B. being

C. are

D. are being

Câu 1: In 1850 ........................ established one of the first detective agencies in theUnited States.

A. it was detectivePinkerton

B. detective Pinkerton 

C. detective Pinkerton who

D. when detectivePinkerton

Câu 2: Commercial centers are ................ they were many years ago.

A. as popular than

B. the most popular

C. the most popular than

D. more popular than

Câu 3: Choose the correct answer A, B, C or D.

A. less convenient as

B. less convenient than

C. not so convenient than

D. the most convenient as

Câu 4: Ansel Adams was a landscape photographer ............................. photographs show the nature of the western United States.

A. of his

B. whose 

C. of whom

D. his

Câu 5: In 1849, Walter Hunt, ...................... American inventor, patented a designthat served as the basis for modem safety pins.

A. an

B. he was an

C. who

D. was an

Câu 6: The journey, ........................ alone for most of the way, was in the name of charity.

A. I undertook

B. that I undertook

C. which I undertook

D. undertaking