According to a UN report one third of the world population have no to clean drinking water

问题补充：

According to a UN report，one third of the world population have no to clean drinking water and health care.

A. means

B. approach

C. channel

D. access

答案：

A. means

B. approach

C. channel

(答案→)D. access

解析：A. means方法，手段，B. approach方法，途径，C. channel频道，D. access获得…的机会，词组：have（no）access to有（无）获得…的机会，句意：根据联合国的报告，三分之一的世界人口没有获得干净的饮用水和健康护理的机会。选D。