There is _______”u” and ______”s” in the word “use”

I rang the bell for a long time last night, but no one opened the door.— Oh, the family __________ a party and they didn’t hear the bell.

As your spoken English gets better, _______ your written English.

There is ________ useful book on the desk， _________ useful book belongs to my brother．

Let’s play _________football instead of playing _______ violin. —Good idea.