All hands shall be feeble, and all knees shall be weak as water.

手都发软，膝弱如水。

youdao

Sir, I am only just getting well of a fever, and I am as weak as water.

先生，我刚从感冒中恢复一些，我极度脆弱。

youdao

He would have worked for his exams all May if his friends had left him alone. Unfortunately they didn't, and he's as weak as water when it comes to saying "no" to a friend.

如果他的朋友们不来打扰，他整个5月都会准备迎考的，但令人遗憾的是他们常来，而他又性格软弱，不好意思对朋友说“不”字。

youdao

Rising seas pose some of the biggest emerging challenges to the world, as coastal urban areas face higher water and dangerous storms, protected only by weak, sometimes crumbling 20th-century flood defenses.

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Pepsi Bottling Group struggled against the weak economic conditions in the United States as consumers cut spending on discretionary items, including bottled water, as the cost of fuel and other food pressed on their wallets.

FORBES: Magazine Article