教练让我们蹲下保持平衡。

The coach told us to ___crouch down to maintain balance.

猫看到陌生人时会蹲下身子，保持警惕。

The cat ___crouched down when it saw the stranger, staying alert.

猫咪蹲伏在草丛中，准备扑向那只蝴蝶。

The cat ___crouched in the grass, ready to pounce on the butterfly.