1 sentence

1. 在真空中，无线电波也是以光速传播的。

   zài zhēn​kōng zhōng, wú​xiàn​diàn​bō yě shì yǐ guāng​sù chuán​bō de.

   In a vacuum, radio waves also travel at the speed of light.

   Source: Dong Chinese Dictionary