Checknut
防松螺母, 保险螺帽, 锁紧螺母
🗣️ 情景例句
Attending school is compulsory in this country.
这国家衽的是义务教育。
Do you mind if I turn off the light?
我把灯关了，好吗？
Lined up against the wall, there were long thin wires attached to metal spheres.
靠墙排列着许多细长的电线，而电线又连着金属球。