By the age of 40, some people are already experiencing breathlessness.

到40岁时，有些人已经感到气绝。

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But breathlessness could also indicate a heart attack or heart failure.

但是，呼吸困难也可能暗示心脏病发作或心衰。

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Even then, there may be breathlessness requiring oxygen to be given by mask.

即使在当时，可能会有呼吸困难，需要氧气，以给予的面具。

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There had been no sign of either breathlessness or chest pain before the heart attack.

心脏病发前并未出现呼吸困难或胸痛的病征。

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There had been no sign of either breathlessness or chest pain before the heart attack.

心脏病发前并未出现呼吸困难或胸痛的病征。

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