将标准状况下，1体积水溶解700体积氨气，所得溶液密度为0.9g/cm^-3，该氨水的物质的量浓度和溶质质量分数分别为（　　）

A．18.4mol/L；38.5%

B．18.4mol/L；34.7%

C．20.4mol/L；38.5%

D．20.4mol/L；34.7%

They claimed that（）1,000 factories closed down during the economic crisis.

A.sufficiently

B.approximately

C.considerably

D.properly