This is the end of this simple food chain.

这就是简单的食物链例子。

The toilet paper industry with its comparatively simple supply chain, should be able to weather the virus more than most.

有着相对简单的供应链的卫生纸行业，理应比大多数（行业）更能抵抗病毒。

This is just a really simple little gold chain, and on it here is a New York subway token.

这只是一条非常简单的小金链，上面是纽约地铁标志。

For more than 50 years, scientists have tried to understand how proteins — the building blocks of biology — transform from simple chains of amino acids into precisely-folded 3D structures.

50 多年来，科学家们一直试图了解蛋白质——生物学的基石——是如何从简单的氨基酸链转变为精确折叠的 3D 结构的。