This cake is very sweet. You      a lot of sugar in it. 

Mr. Smith is always on time for everything. How ________ it be that he was late for the flight?

We find ------interesting to learn history.

—The research on the new flu virus vaccine is challenging and demanding. Who do you think can do the job?—________ my students have a try?

 —Must I go to medical school and be a doctor like you, dad?—No, you _______,son. You’re free to make your own decision.