Samuel Clemens,______ Mark Twain, wrote many popular stories.
Our school requires that all students _______ on the campus.
At the routine office meeting, the headmaster insisted that the problems _______ paid special attention to.
_______ basic first-aid techniques will help you respond quickly to emergencies.
People develop _______ preference for a particular style of learning at _______ early age and these preferences affect learning.
She ________ someone, so I nodded to her and went away.