The boy insisted that he __________ nothing wrong and that he __________ at once.

—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?

—Listen! There is a knock on the door. Who _____ it be?—It must be Jack. Just now I sent for him.

—________ I smoke here?—No. You are not allowed to smoke in public places.

My brother is honest. He _____ such a thing.