乘坐57路公交车用英语可以说成 "Take the 57 bus."
"Take" 是动词，意思是 "乘坐"。"the" 是冠词，用来修饰名词 "57 bus"。"57 bus" 是名词短语，表示 "57路公交车"。
例句：
I need to take the 57 bus to work. (我需要乘坐57路公交车去上班。)
Can you tell me when the next 57 bus arrives? (你能告诉我下一辆57路公交车什么时候到达吗？)
The 57 bus is always crowded during rush hour. (在高峰时段57路公交车总是挤满人。)