The bus ____ at six, but it arrived an hour later.

In China's countryside, villagers often have the same family name, but ________ not be closely related.

Something terrible _________ if he didn’t come to the bar as he always did.

For those of you who ________ a few very popular articles that came out last week, check out this mail.

---who______it be that is knocking at the door? ---It_______be Father, but I’m not sure.