A.1,73.
B.1,20.
C.1,59.
D.1,32.

A.Tơ nitron được điều chế bằng phản ứng trùng ngưng.
B.Sợi bông, tơ olon đều thuộc loại tơ thiên nhiên.
C.Cao su lưu hóa có cấu trúc mạch không phân nhánh.
D.Tơ nilon-6,6 được điều chế bằng phản ứng trùng ngưng.

A.CrS.
B.CrSO4.
C.Fe2(SO4)3.
D.Cr2(SO4)3.

A.Fe3O4.
B.Fe(OH)2.
C.FeO.
D.Fe2O3.

A.Na2SO4.
B.NaCl.
C.HCl.
D.Na2CO3.

A.Urbanization minimizes risks for economic, cultural and societal development.
B.Urbanization makes water supply system both efficient and effective.
C.Weather and climate in the city will not be improved.
D.People may come up with new ideas for innovation.

A.Population
B.Development
C.Urbanization
D.Unsanitary condition

A.meaningful
B.severe
C.deep
D.right

A.Infrastructure and Economic Activities in Cities
B.The Risks of Rapid Urbanization in Developing Countries
C.What Has Driven Rapid Urbanization?
D.The Global Risks 2015 Report on Developing Countries

A.Infrastructure and Economic Activities in Cities
B.The Risks of Rapid Urbanization in Developing Countries
C.What Has Driven Rapid Urbanization?
D.The Global Risks 2015 Report on Developing Countries