—Who______ it be that is knocking at the door?—It ______ be Father, but I’m not sure.
Write to me as soon as possible when you __ Beijing.
We fed the milk ___ the bird means we fed the bird ___ milk.
I heard some very ___news this morning.
My little sister had an apple in __ his hands.
Reagan was elected ___ of the United States in 1981.