英语语法分析

An unclenched fist?

松开的拳头？

But he stressed that, while his fist was still unclenched, the onus was on Iran to grasp it.

但是他强调说，虽然他的拳头依旧是松开的，但是要不要抓住这只松开的手，应该是伊朗方面的问题。

Keep your hands in an unclenched fist, with your fingers lightly touching your palms. Imagine yourself trying to carry a potato chip in each hand without crushing it.

保持双手半握拳，手指轻抵手掌，恰似你每只手攥着一片薯片，但不能压碎它的感觉。