Definition (空間)
A very small opening or narrow gap.
（只）留一條縫
She opened the door just a crack so she could hear what was going on outside.
她把門打開一條縫，這樣她就能聽到外面的動靜。
I left the window open a crack to let some fresh air in.
我把窗戶開了一條縫，讓一些新鮮空氣進來。
He opened the box a crack to peek at what was inside.
他把盒子打開一條縫，偷看裡面有什麼。