In a car or a motorbike, the engine spins very fast. The wheels need different kinds of spin — slow and strong when you start, quicker when you are already moving. The gearbox is the box of toothed wheels (gears) that changes that relationship.

In a car or a motorbike在汽車或摩托車裡 the engine spins very fast引擎轉得非常快。 The wheels need different kinds of spin輪子需要不同種類的轉動 — slow and strong when you start剛起步時要慢而有力 quicker when you are already moving已經在移動時要快一點。 The gearbox is the box of toothed wheels (gears)Gearbox（變速箱）就是那個裝滿有齒輪子（gears）的箱子 that changes that relationship負責改變這種轉動關係

When you “change gear”, you are asking the gearbox to pick a different pairing. Manual cars let you choose; automatic cars have a gearbox too, but the car chooses for you.

When you 'change gear'當你「change gear（換檔）」時 you are asking the gearbox to pick a different pairing就是在要求變速箱選一個不同的搭配組合。 Manual cars let you choose手排車讓你自己選； automatic cars have a gearbox too自排車也有變速箱 but the car chooses for you只是車子替你選

Gearbox is the usual British word, and it points quite tightly at that box of gears. American English often says transmission for the wider system. Though actually, in everyday talk people use the two as if they were the same thing.

Gearbox is the usual British wordGearbox是英式英語常用的說法 and it points quite tightly at that box of gears它指的相當精確地就是那個裝齒輪的箱子。 American English often says transmission美式英語則常用transmission for the wider system來講整個比較大的系統。 Though actually不過事實上 in everyday talk people use the two as if they were the same thing在日常對話裡，人們常常把這兩個字當成同一件事來用

You will also hear it on bikes, buses, and some machines that are not cars at all — anywhere a set of gears sits in a case and passes power along.

You will also hear it on bikes, buses, and some machines that are not cars at all你也會在腳踏車、公車，還有一些根本不是汽車的機器上聽到這個字 — anywhere a set of gears sits in a case and passes power along只要是一組齒輪裝在一個殼子裡、負責傳遞動力的地方，都可能用得上