By last passing of the finish line there will be a bell ringing indicating final lap, which could be earlier than scheduled if necessary.

通过终点线进入最后一圈时会打铃提醒，如果有必要也会减少预定圈数而提前打铃。

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After trailing by more than three seconds with a kilometer still to go, Jensen gradually clawed his way back and was just 0.16 seconds behind at the bell lap.

CNN: Records tumble at last day in pool

McIlroy led at the bell after a slow opening lap (55.83) but he was passed by the majority of the field with 300 metres left.

BBC: McIlroy exits in Munich

Sir Roger used the original bell used in 1954 to signal the final lap.

BBC: SPORT | Athletics | Bannister relives mile