() a device that can automatically stop an electric current if it becomes dangerous（自动断电的）断路器 () a rule that automatically stops or slows trading on a stock exchange when prices rise and fall too quickly or too far自动停板规则（当股价上升和下降太快或幅度过大时，证券交易所采取的自动停止或减少股票交易的规则）◆circuit-breaker trading自动停板交易◆How many times can the circuit breaker be triggered during the day?在一天的交易中，自动停板规则能用多少次？