Knuckle under without a fight?
不抵抗就屈服？
Even if times get tough, they don't knuckle under.
即使面临困难的时候，他们也不屈服。
You can can fail successfully, also, you can not knuckle under but.
你可以胜利，也可以失败，但你不能屈服。
He would not knuckle down under their pressure.
他不会在他们的压力下屈服的。
He would not knuckle down under their pressure.
他不会在他们的压力下屈服的。
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