灯泡必须正确拧入灯座才能正常工作。

The light bulb must be screwed properly into the ___socket to work correctly.

房间角落里的插座松动了，我需要找人来修理。

The ___socket in the corner of the room is loose, I need to get it fixed.

髋关节的球状部分嵌入骨盆的凹槽中。

The ball-shaped part of the hip bone fits into the ___socket of the pelvis.