史上最知名的類比「I have a dream」by Martin Luther King, Jr. 利用白人小孩與黑人小孩玩在一起來類比一個沒有種族歧視的世界 -> [bb]https://www.youtube.com/watch?time_continue=85&v=3P_s3ChZlRY&feature=emb_logo[/bb]
A tank truck usually holds between 4,000 and 6,000 gallons of gasoline. Depending on the tanker, three to six individual compartments hold 600 to 900 gallons of gasoline apiece. The tank that contains the compartments is elliptically shaped to distribute the pressure equally and to allow a more complete flow of air when the gasoline is delivered.
Until recently the only way to load a tanker was to climb up on top, where the openings to the compartments are located. You can easily picture this by visualizing six pop bottles lined up in single file on a table. A man wants to fill up bottle three, so he takes the cap off. He then inserts a small hose into the neck of the bottle and turns on a faucet which is connected to the hose.
A gasoline tanker is loaded in a similar way, but on a much larger scale. A man climbs on top of the tanker and opens a particular compartment by removing the cap. He then takes a hose with a four-foot metal pipe down into the “bottle” (the compartment hole), which measures four inches in diameter. A pump is then turned on, allowing the gasoline to flow into the compartment.