多功能数字钟：在手动校时功能时，选择是调整小时，还是分 若长时间按住该键，还可使秒信号清零，用于精确调时 -Multi-function digital clock: In the manual, when the school functions, the option is to adjust hours, or minutes, if a long time hold the key, so that second signal can be cleared for accura