齿条齿轮

rack and pinion

tooth / CL:顆|颗[ke1]

rack (and pinion)

strip / item / article / clause (of law or treaty) / classifier for long thin things (ribbon, river, road, trousers etc)

(machine) gear / pinion (gear wheel)

wheel / disk / ring / steamship / to take turns / to rotate / by turn / classifier for big round objects: disk, or recurring events: round, turn

wheel; disk; ring / steamship / to take turns; to rotate / classifier for big round objects: disk, or recurring events: round, turn