Read the following passage and mark th...

Câu hỏi: Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34.

A. Factors bringing about the development of human cities 

B. How population density affects the development of human cities 

C. Why a shared language makes a peaceful human city 

D. Problems solved by cooperation of a large group