while
- While Suzy ______ on the sofa, the phone rang.
- While Mary ___ a letter, the children were playing outside.
- While I ___________ TV, the bell rang.
- While he was investigating ways to improve the telescope, Newton made ________ discovery which completely changed ________ man’s understanding of color.
- While shopping, people sometimes can’t help ________ into buying something they don’t really need.