.The businessman asked a much ______ price than ______.

 We are short of clean safe drinking water, which is found to be the ______ in many third world countries.

An increasing number of people enjoy sun-bathing, but experts warn that too much ________of the body to strong sunlight is harmful．

 David had prepared carefully for the exam so that he could pass it at his first ________.

 We should develop the sunshine project actively, because it can save _______ resources as well as reduce pollution.