—Have you ___________? —No. I had the wrong number.
If you don’t learn to think _____ you are young, you may never learn.
A new way of teaching _____ in the article can make learning easier.
My mother asked me where _____, and I told her that I was going to buy some food.
I still don’t know ______ she’s planning to come to my birthday party or not.
— Could you give _______ an introduction to the new machine?— Of course. I will tell you how to use it.