---What are you doing? ---- I am _____ a letter.
A.sending B. writing C.Both A and B
________ he ________maths problems at school?
A．Do；do B．Does；does C．Does；do
He ________ stay at home.
A．have to B．has to C．musts
There are some books ________ boys.
A．for B．of C．to
Can you play ________ football?
A．/ B．a C．the
—Are there ________ games in your school?
—Yes，there are.
A．some B．any C．a little