—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.
—I'm sorry I didn't make it to your party last night. — __________. I know you're busy these days.
__________ to the sun for a long time will do harm to your skin.
His __________ description of his adventure in the forest made us want to have a try ourselves.
I don't want any reward for my help; I gave it __________ out of friendship.
Nowadays,there is a __________ increase in children's creativity, for they are greatly encouraged to develop their talents.