To grab at means to try to get hold of someone or something quickly, with your hand.

试图抓住的意思是尝试用手快速抓住某人或某物

He was clumsily trying to grab at Alfred's arms.

他正笨手笨脚地试图抓住艾尔弗雷德的手臂。

Greatly alarmed, he made a grab at the side of the boat, and the next moment--Sploosh!

他吓了一大跳，伸手去抓船边，不一会儿——扑通一声！

He'll grab at any excuse to avoid doing the dishes.

他会随便找个借口来逃避洗碗。

A drowning man will grab at a straw.

“快淹死的人连一根稻草也要抓的。”。

Rose rushed at dieter and made a grab at his wrist.

罗斯冲向迪特尔抓住他的手腕。