4 sentences

1. 科学家如何测量光速？

   kē​xué​jiā rú​hé cè​liáng guāng​sù?

   How do scientists measure the speed of light?

   Source: CCMatrix

2. 光速可以被降低吗？

   guāng​sù kě​yǐ bèi jiàng​dī ma?

   Can the speed of light be slowed down?

   Source: CCMatrix

3. 假设对于这两个观察员而言，光速是相同的。

   jiǎ​shè duì​yú zhè liǎng​ge guān​chá​yuán ér​yán, guāng​sù shì xiāng​tóng de.

   Assume the speed of light is the same for both observers.

   Source: UM-Corpus: Education

4. 任何东西都不能逃脱黑洞的引力，因为没有任何东西的速度能超过光速。

   rèn​hé dōng​xi dōu bù​néng táo tuō hēi​dòng de yǐn​lì, yīn​wèi méi​yǒu rèn​hé dōng​xi de sù​dù néng chāo guò guāng​sù.

   Nothing can escape a black hole’s gravity because nothing can travel faster than the speed of light.

   Source: CCMatrix