健身前我会先活动手腕，轻轻弯曲几下。

Before working out, I gently ___flex my wrists a few times.

他在健身房里展示他的肌肉。

He ___flexed his muscles at the gym.

学校需要灵活调整课程以满足不同学生的需求。

The school needs to ___flex its curriculum to meet the needs of diverse students.