It is __________ to spend money on preventing illnesses by promoting healthy living rather than spending on trying to make people ___________ after they are ill.

Only then did he             the effects of his action.

Facing this ________ problem, I found myself ________ about how to work it out.

Those T-shirts are usually ＄35 each, but today they have a (an)＿＿＿price of ＄19 in the shopping center. 

As there is less and less coal and oil, scientists are exploring new ways of making use  of ______________   energy, such as sunlight, wind and water for power and fuel.