Trying to apply new methods to projects that have established deadlines is difficult, and often impossible.

在确定了最终期限的项目中运用新的方法是相当困难的，通常是不可能的。

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But the prime minister also admits that in a country where HIV and AIDS victims are often abandoned by their families, fear of the disease could make it almost impossible to stop its spread.

VOA: standard.2009.04.04

These linkages are largely unknown and often impossible to observe, quantify and measure.

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The necessary problem-solving skills are difficult to teach, and the experience is often impossible to acquire because so much is new.

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Often they make it impossible for mothers with pushchairs, and often walking small children, to pass without dangerously going out into the road.

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