‘How come‘ is used a lot in conversation and friendlier styles of writing:
– “I decided not to take that job.”
– “Really? How come?”
– “How come you aren’t going out tonight?”
– “I won’t be able to come tomorrow, sorry.”
– “Oh no, how come?”
– “So how come he got the job and not me?”
As you might be able to guess, how come is used to ask why or how something has happened.
It can be part of a whole sentence or as a fixed “How come?” when the context or situation is clear.
We particularly use it to talk about other people or to mention a situation involving other people.
So you’ll hear how come + he/she/we/they quite often.
You’ll also hear it with ‘so’:
“So how come he’s here so often?”
“So how come you haven’t offered Tegan the job?”
Grammatically there’s one key difference compared to using ‘why‘:
– “Why did he go home?”
– “How come he went home?”
As you can see, why uses an auxiliary verb (did in the above example), whereas how come is written like a regular sentence (ie subject + verb).
– “Why is she tired?”
– “How come she is tired?”
Most importantly, why is it good to use ‘how come?‘? Well, it sounds a bit softer, a little less inquisitorial.
It sounds a bit more matter of fact and that’s one reason we use it more in conversation.