be worried about his safety______, he is aneighteen-year-old young man

He doesn’t eat pork, but ______ that he’ll eat just about anything.

“Would you mind if I _______ one of these books？” “_______.”

Until I was twenty-three I never ________ attending night school three nights a week.

I _____ him to give up drinking, but he wouldn’t listen to me. [ ]