Steam locomotives were superseded by diesel.是什么意思？

Steam locomotives were superseded by diesel.

蒸汽机车被内燃机车取代了.

steam

n. 蒸汽，雾，〈口〉精神，精力，轮船，乘轮船旅

例句
...the age of steam and steel.
蒸汽和钢铁时代

locomotives

n. 火车头，机车( locomotive的名词复数 )；

例句
Steam locomotives pumped out clouds of white smoke.
蒸汽机车喷出一团团白烟。

were

be的过去时复数和第二人称单数形式，有时代替 was,用于条件从句、动词 wish 之后等；

例句
Shops, houses, and vehicles were set ablaze.
店铺、房子和车辆全都陷于火海。

superseded

adj. [医]被代替的，废弃的；v. 取代，接替( supersede的过去式和过去分词 )；

例句
Hand tools are relics of the past that have now been superseded by the machine.
手工工具是历史的遗物，现在已经被机器所取代。

by

prep. 在…旁边，表示方式，由于，经过；adv. 经过，表示保留或保存时用，短暂拜访；

例句
...expensive make-up that we saw being advertised by a beautiful model...
我们所见的由一位漂亮模特代言的昂贵化妆品

diesel

n. 柴油机，柴油机机车（或船等）；

例句
The air is so black with diesel fumes and coal dust, I can barely see.
空气中充斥着柴油烟雾和煤尘粉末,黑乎乎的,我几乎什么都看不见。