Câu hỏi: 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 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: The harder this man works, ....................... he becomes.

A. most successful

B. more successful

C. the more successful

D. the most successful

Câu 3: 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

Câu 4: Willa Cather, ....................... a prominent American writer, grew up in Nebraska during the early farming years. 

A. who became

B. became

C. she became

D. it is she who became

Câu 5: Samuel Clemens, ................ under the pen name Mark Twain, createdcharacters that reflected purely American life.

A. he wrote

B. was writing

C. wrote

D. who wrote

Câu 6: 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