are your parents going to work___ bikes or____bus?

问题描述:

are your parents going to work___ bikes or____bus?
A on their;by B by;by C on;on the D by;on a

选A,如果是用By bike 那么bike要用单数,而现在题目里的bikes是复数,所以不能用by,最后选A,也是一个固定搭配.