12．Could you please explain 你能解释一下……吗 13．Can't we... 难道我们不能……吗 14．Could you do me a favor and... 能否请你帮我一个忙… 15．Do you by any ...

See? “By” originally means “bye” or byway. That’s why, in fact, some people still spell “by the by” as “by the bye”. By the way, “that is by the by or bye” in this sense (secondary) is an idiom that ...