When we are tired, tense, depressed, or unwell, we feel pain much more.

当我们疲劳、紧张、沮丧或者身体不适时，就更觉得疼。

《柯林斯英汉双解大词典》

It would be like asking a marathon runner if they feel pain.

就像你去问一个马拉松运动员他们是否感到疼痛。

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A three-year-old might need help in understanding that other children feel pain just as he does, and that hitting a playmate over the head with a heavy toy requires an apology.

一个三岁的孩子可能需要他人帮助，才能理解其他孩子也和他一样会感到疼痛，用玩具重重地打了玩伴的头是需要道歉的。

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But if deeper tissue is affected, a person is likely to feel pain every time the area gets cold.

VOA: special.2009.12.23

You take a pin and you stick it through my flesh of my body and I feel pain in my soul, in my mind.

你拿一根针扎我身体上的肉,我的灵魂,我的心灵就会意识到疼痛

耶鲁公开课 - 死亡课程节选

If it's possible, use animals that don't feel pain, or use lower forms of life.

如果可以的话，请使用那些感觉不到疼痛的动物，或者用低级生物。

需要动物实验吗？ - SpeakingMax英语口语达人

But who are these heartland Americans who are unable to feel pain and sadness?

ECONOMIST: The secret of happiness

He claimed he could use it to show humans weren't the only ones to feel pain.

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Those told he could not feel pain, pleasure or fear were much more unnerved.

ECONOMIST: Why androids are scary