Tom looked upon the test as an obstacle _____ his classmates regarded it as a challenge.
Most people are familiar with the idea that all matter in the universe ________ atoms.
________, Nathan gave back the enormous amount of money he found.
________ entered the classroom ________ the bell rang.
— Did you remember to give Jenny the money? — Yes. ________ I saw her, I’m sure.
______ their homework, these three students have to stay in the classroom for another thirty minutes.