【英语时差8,16】光速与星际高速路（上）

If you’re driving on an interstate highway, the only thing keeping you from going faster than the speed limit is your sense of civic¹ duty, or perhaps that police car up ahead. There’s one speed limit, however, that most scientists agree nothing will ever break. That’s the speed of light: 186,280 miles per second. As it travels through deep space, light moves at exactly this speed, no more and no less. The speed of light is so reliable², we even use it to measure distances between the stars. If it takes starlight fifty years to reach us, we say that this star is fifty light-years away. You might be surprised to learn, however, that light itself does not always travel at the speed of light. Our interstate highways generally have a higher speed limit, but once you enter a city or residential³ street, the speed limit lowers⁴.

1 civic   

adj.城市的，都市的，市民的，公民的

参考例句：

• I feel it is my civic duty to vote.我认为投票选举是我作为公民的义务。
• The civic leaders helped to forward the project.市政府领导者协助促进工程的进展。

2 reliable   

adj.可信赖的；可靠的

参考例句：

• I'm afraid the information is not reliable.恐怕消息不可靠。
• Do you think she's reliable?你看她这个人可靠吗？

3 residential   

adj.提供住宿的；居住的；住宅的

参考例句：

• The mayor inspected the residential section of the city.市长视察了该市的住宅区。
• The residential blocks were integrated with the rest of the college.住宿区与学院其他部分结合在了一起。

4 lowers   

v.（使）降低， （使）跌落( lower的第三人称单数 )；削弱；削减；减少

参考例句：

• The reduction in white blood cell counts lowers resistance to disease. 白细胞总数的减少，会降低对疾病的抵抗力。 来自《简明英汉词典》
• The sun lowers in the west. 太阳从西边落下。 来自《简明英汉词典》