I am trying to explain compost

my Chinese guest  is looking puzzled

any vegetable waste,  peelings, tea, coffee grounds ... put them in here  

I point at the kitchen waste bucket, she shrinks back in horror. Maybe I need to show more of the process, I pick up the bucket and beckon her to follow me up the garden, open the compost bin and tip the bucket  into it. She looks stricken 

Why would you do that?

It feeds the garden, the worms and insects break it down to make a rich soil - don't you feed your garden?

I feed my garden with yellow beans 

!!!