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

A. that are

B. being

C. are

D. are being

Câu 1: 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 2: The harder this man works, ....................... he becomes.

A. most successful

B. more successful

C. the more successful

D. the most successful

Câu 3: 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 4: 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 5: I ..................... you a copy of the article tomorrow.

A. send

B. was sending

C. will send

D. will be sent

Câu 6: 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