Distance education programs the disadvantages of limited time, distance or physical disability, so they are becoming more and more popular all over the world.
Doctors say that exercise is important for health, but it ________ be regular exercise.
One of our rules is that every student ________ wear school uniform while at school.
The new law states that people ________ drive after drinking alcohol.
—Good morning. I've got an appointment with Miss Smith in the Personnel Department. —Ah, good morning. You ________ be Mrs. Peters.
It ________be the postman at the door.It's only six o'clock.