—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.
It was ______ he said ______ disappointed me.
_______ fun it is to jump into a pool or go swimming in summer.
_______ is it _____ has made Peter _______ he is today?
Many people apply ___ the position as a salesman in this company.
Sometimes there are papers or books to collect or to ___.