undulations

"My brother is a talented guitarist. "

"The dew on the grass was shimmering in the morning sun. "

"His sudden appearance surprised me."

"My mother's instance that I finish my homework before dinner was quite strong. "

"Her voice was tremulous as she announced she had won the scholarship. "

"The photo of my old school reminded me of my favorite teacher. "

"Her distinctive laugh, a high-pitched giggle, could be heard across the entire playground. "

"heat radiation"

"The cell phone emits electromagnetic waves that allow us to communicate. "

"The guard blew his whistle to indicate imminent departure."

"The breeze was gently undulating the tall grass in the field. "

"The complicated instructions on the new software difficult me from completing the project on time. "