我来回答一下这三个短语的区别。
get on the bus是动词短语,中文意思是“上公共汽车”,take a bus中文意思是“坐公交车”,而by bus的中文意思是“乘公交车”。
举例子说明一下。
He got on the bus, and then got off at the hospital.
He often takes a bus togo to the zoo.(作谓语)
He often goes to the zoo by bus. (作状语)
希望我的回答能够尽快帮到你啊!