clockwork
noun [ U ] uk/ˈklɒk.wɜːk/ us/ˈklɑːk.wɝːk/
（时钟、玩具等的）发条装置
a system of springs and wheels that you wind (= turn) with a key or handle to make some clocks, toys, and other devices operate
a clockwork train/mouse 发条玩具火车／老鼠
Idioms
like clockworkidiom (also (as) regular as clockwork) 非常有规律;极为准时
very regularly, or at exactly the planned times
Since the recent improvements to the service, the buses are running like clockwork. 最近，自从改进服务后，公交车运行得非常准时。
My daughter always calls me every Friday evening, (as) regular as clockwork. 我女儿总是每星期五晚上给我打电话，非常准时。
run/go like clockworkidiom 准时进行；顺利进行
to happen exactly as planned, without any trouble
The party went like clockwork. 晚会进行得很顺利。