すばしこいnimble, smart, quick

小(ちい)さな子供(こども)はすばしこく立(た)ち回(まわ)ります。

Small children move around nimbly.

すばしこい動作(どうさ)を目(め)で追(お)うのは疲(つか)れます。

Following quick movements with your eyes is tiring.

すばしこくチョロチョロ動(うご)く赤(あか)ちゃんの子守(こも)りは大変(たいへん)だ。

Looking after a baby who moves around quickly and nimbly is difficult.

スズメのすばしこい動(うご)きを写真(しゃしん)におさめるのは不可能(ふかのう)だろう。

It's probably be impossible to capture the nimble movements of a sparrow in a photograph.

動物(どうぶつ)の動(うご)きはすばしこい。網(あみ)や素手(すで)で捕(つか)まえようにも捕(つか)まえられません。

The movements of animals are fast and nimble. Even if you try to catch them with a net or bare hands, they're uncatchable.