— Is John coming over this weekend?— He should, but he _______ not. He seems to be busy these days.

—Why didn’t Susan come to school? —I don’t know. She____ ill.

We would have called a taxi yesterday if Harold __________us a ride home.

As a graducate in computer science, he ___ to work out the problem.

I must go there earlier. John has suggested that I _____an hour before the discussion begins.