The average Facebook user in the United States has 245 friends,according to a study ______in February.
Every farmer knows that weather _________ farming.
—Please __________ us in the discussion. —I'd like to, but I'm __________ busy at the moment.
—Are you free tomorrow afternoon? —I'm afraid not. I'll have to ________ an important lecture given by a famous professor.
He divided the sweets __________ the children who were divided __________ three groups.
America and England are two countries ________ by a common language.