【英语时差8,16】耗油卡车（下）

 Here's why. A closed tailgate sets up a bubble of air that slowly circulates in the bed of the truck. Air coming over the cab of the truck treats the bubble as a smooth cover over the bed, and passes over this “cover” without ramming¹ into the tailgate. Opening the tailgate breaks up this smooth bubble of air. The air then rushes over the cab, and quickly down into the bed. This creates a lot of turbulence², which results in more drag. So technically³ speaking, with the tailgate open the shape of the truck is not as aerodynamic as it is with the tailgate closed. So, gas mileage⁴ is better with the tailgate closed. Actually you probably wouldn’t notice much improvement at lower speeds, but at highway speeds of sixty miles-per-hour and above you should get slightly better mileage. Also, the truck is structurally⁵ stronger with the tailgate up, so that’s two good reasons to keep it closed. Well, maybe a third would be to keep the trash you’re hauling from spilling onto the road, but that’s another story.

1 ramming   

n.打结炉底v.夯实（土等）( ram的现在分词 )；猛撞；猛压；反复灌输

参考例句：

• They are ramming earth down. 他们在夯实泥土。 来自辞典例句
• Father keeps ramming it down my throat that I should become a doctor. 父亲一直逼我当医生。 来自辞典例句

2 turbulence   

n.喧嚣，狂暴，骚乱，湍流

参考例句：

• The turbulence caused the plane to turn over.空气的激流导致飞机翻转。
• The world advances amidst turbulence.世界在动荡中前进。

3 technically   

adv.专门地，技术上地

参考例句：

• Technically it is the most advanced equipment ever.从技术上说，这是最先进的设备。
• The tomato is technically a fruit,although it is eaten as a vegetable.严格地说，西红柿是一种水果，尽管它是当作蔬菜吃的。

4 mileage   

n.里程，英里数；好处，利润

参考例句：

• He doesn't think there's any mileage in that type of advertising.他认为做那种广告毫无效益。
• What mileage has your car done?你的汽车跑了多少英里？

5 structurally   

在结构上

参考例句：

• The house roof was (structurally) unsound. 这屋顶（结构）不牢固。
• Pinhole on shot-hole damage is never structurally significant. 针孔和蛀洞所造成的危害对结构的影响不大。