Swimming is the best way to tone up your body.
游泳是健体强身的最好方法。
In telephony, the use of tones to transmit supervisory, address and alerting signals over a circuit.
在电话技术中, 利用音调在电路中传送监控、地址和报警信号的做法。
A tone or value halfway between a highlight and a dark shadow.
中间色, 半调色在光线最强处与黑色暗影之间的一种色调或明暗的配合
