那我去拿一把沙子搓搓看。

Let's take a handful of sand and rub it.

他抓起一把沙子，让它从指缝间滑落。

He grabbed a fistful of sand and let it slip through his fingers.

一滴水并不足以显现出漩涡，而一把沙子也不足以引发沙丘的崩塌。

One drop of water is not enough for a whirlpool to appear in, just as one pinch of sand is not enough to hatch an avalanche.