agonize

"The children physically exhausted themselves playing tag in the park. "

"The student agonizing over the difficult math problem felt a sharp pain in his head. "

"The student's anguish over failing the exam was evident in her slumped posture. "

"My brother constantly helps his younger sister with her homework, demonstrating his steadfast loyalty and support. "

"The violent assaulted the student in the school hallway. "

"The student desperately craved a good grade, working late into the night, neglecting his health. "

"He is a student of life."

"The tadpole changed into a frog.   Stock prices are constantly changing."

"He mentally reviewed the math problems before answering them aloud. "

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

"The gymnast's struggle to hold the difficult handstand was impressive. "

"She frowned when I told her the news."