Just because the other kids have motor scooters is no reason for you to stop riding your bike to school.
只是因为其他的孩子都有电单车上学,不足以成为你不骑车上学的理由。
This depends on the precise radio frequency of the 21-cm wavelength, or 1420 megacycles per second.
这种通讯联系要靠21厘米波段,即每秒1420兆周的精确无线电频率。