Umn
abbr. upper motor neuron 上运动神经元
🗣️ 情景例句
We must prepare ourselves to have a hard time.
我们必须准备过艰苦的日子。
Is anybody home?
有人在家吗？
They had just had enough time to swim out of danger when the boat again completed a circle.
他们刚刚来得及游出危险区，快艇就又转完了一圈。