Dr. Ma is strict ______ local doctors and nurses, especially________their skills.

Bob never does his homework_____Mary. He makes lots of mistakes.

I haven’t seen Tom for a long time. Is he ill—_____. His teacher told me he was in hospital.

“Attention, please. Whoever can answer one of my questions _____ receive a prize,” the teacher saidin class.[ ]

The kid isn’t old enough to go to school.